I think you've got a lot of colors going on right now, so you should leave the ceiling the same white as your trim. Why would you want a color that makes your ceilings feel less tall? Why would you want them to compete with your walls for attention? More isn't more, especially with the farmhouse style. Plus any light gray could react with your blues and greens in an unexpected way.

For a white that isn't too white, try BM American white or dove white. These would both also be suitable for trim. For your grayish green, BM Halo might be perfect. Not sure of a SW match.

You should consider a SW color consult. They come to your home and it's only about $100.

Benjamin Moore recommends ice mist with Stunning https://www.benjaminmoore.com/en-us/color-overview/find-your-color/color/826/stunning?color=826

Btw I looked up the LRV of your paint colors and they are all REALLY dark. Have you painted actual swatches on the wall or a piece of poster board?
Your navy is going to read almost black. Your ceiling preference, grayish, is going to be so dark that it absorbs light, not reflects it. None of these choices really seem to fit with the light bright farmhouse trend. The "colors" do, but not the shades. All the windows in the world can only do so much, especially once the sun goes down.

https://www.kylieminteriors.ca/paint-colours-and-lrv-the-ultimate-guide-to-choosing-the-right-colour/

I had color on all my ceilings -- I think it's a good choice to make since it makes woodwork like crown molding really pop. BM has Muskoka Trail

https://www.benjaminmoore.com/en-us/color-overview/find-your-color/color/974/muskoka-trail?color=974&source=%2Fen-us%2Fcolor-overview%2Ffind-your-color%2Fcolor%2Fac-1%2Fcoastal-fog

Use white ceiling paint for every ceiling in the house. Exception: if any room has a wood ceiling with a natural wood finish.

Alternatively, I recommend getting large chips of all the colors & installing the benjamin moore app. In very good light, take a picture of each color and use the app to recommend colors that go with -- since you have several room colors, it will help you zero in on a color that will go with as many as possible

White. There's a very good reason that ceilings are painted white with an especially flat finish. Use white.

I'm leaning towards SW Grayish 6001. I don't mind its purple undertones since purple is my next favorite decorating color next to navy. But, I don't want it to look purple.

Grayish belongs to the yellow-red hue family. It's a low chroma, near neutral color. It doesn't have "purple undertones".

Every color belongs to a hue family and if Grayish shifts and looks different from its hue family, which is objectively determined using a balanced quality of light, like purple, it's because of the of light you're viewing it under. Grayish is not inherently purple.

This is important to know because once you put it on the ceiling, it's going to look darker and grayer and chances are it's going to look like just a "warm gray".

Based on all your suggestions, I'm thinking Grayish will be too dark for the ceilings. I'm now looking at Rhinestone which has LRV of 74 for the ceiling and is part of SW's white collection. Thank you!

Still debating ceiling colors. So I've primed and painted 2 coats on 2x4 foot pieces of sheet rock. Has anyone used SW Snowfall for ceilings? I only get one color for the ceilings and that same color will be used in garage and closets.

All finishes are picked and work with the wall paint colors I've chosen. SW Upward is working as a whole house wall paint. It does exactly what I want - looks white, grey, or pale blue depending on lighting. SW Silver Strand works for our den and goes with the furnishings that will go in that room. BM Stunning is working for our front door, dining, and a bathroom that will have shiplap below. SW says they will match the board for me. High Reflective White seems to work for doors, trim, shiplap and SW says it comes in the semi-gloss latex that our builder uses. Still haven't found the right ceiling paint that will contrast with trim but be light enough. I greatly appreciate all the comments warning me that the paint colors will look darker on the ceiling than on a wall!! House has lots of windows and tall ceilings. Ceilings are mostly 10' but we have two vaulted ceilings plus a two story stairwell that will be entirely in shiplap. Crushed Ice was too dark but I liked that it wasn't too grey or too yellow. I've used it for the walls in a dark condo before, so I had the paint to try it out. Rock Candy was too light, but otherwise worked. Rhinestone was horrible - it is turning green or blue depending on lighting and definitely doesn't work with the wall colors. So now I'm looking at Snowfall SW6000. I want something that reads grey, like Crushed Ice, but is lighter. On the colorography charts, it looks like Snowfall is similar to Crushed Ice but higher value and LRV.

If anyone has experience with Snowfall, please share!

You could always try lightening or darkening by 25%. Just make sure you test because occasionally colors don't stay true.

Crushed Ice was too dark but I liked that it wasn't too grey or too yellow.

Take a look at Heron Plume SW 6070.

Good grief use Sherwin Williams Ceiling Bright White and don't use that awful blue throughout your house.

Here above is a neutral whole house color scheme where other colors can be safely added if necessary

These SW colors below are in the gray/blue range but are way more subtle in color.

Here below are modern farmhouse colors.

So far the house will look like a clown car

Upward is really dark & way too BLUE, not the least bit subtle. How do you expect to coordinate your other finishes???? This color is going to eat natural light. How big is the house? 2,400 sq. ft?

this color below will look twice as dark when applied to the ceiling.

Actually I got different colors that go with Ice Mist BM than Lynne Mysliwiec mentioned.

Here we are

https://www.benjaminmoore.com/en-us/color-overview/find-your-color/color/2123-70/ice-mist?color=2123-70

Shadow Gray, Ice Formation....

BeverlyFLADeziner I appreciate your taking the time to offer your advice, and I realize I need to look for a lighter color for the ceiling. But I found the tone of your answer offensive. Would you like it if I commented on your design work using that same tone while pointing out - from a professional organizer's standpoint - that your ideas were impractical and lacked consideration of storage needs? Perhaps you would be willing to edit your answer to make it more professional.

BM recommends Blue Veil to go with Stunning. Blue Veil is quite similar to SW's Upward but was too light and grey for my taste for a whole house wall color - but I can see where blue veil would be nice as a ceiling color for a room painted in Stunning. As it is, Stunning is an accent color and was picked to match our navy AGA range which is a focal point of the home. The 2'x4' board painted Upward doesn't look as awful as BeverlyFLADeziner makes it out to be - it actually looks lighter and more subtle than the SW color visualizer makes it out to be. We will have white shiplap wainscotting throughout, so that also neutralizes the Upward. I did switch from Sea Salt to Silver Strand for the den because Silver Strand works best with the couch and painting I have.

I'll try Snowfall next for a ceiling color. Lori A. Sawaya I like Heron Plume by itself but next to the paint sample boards it looks too beige for my taste and didn't work with the wood beams and floor samples I have.

Lynne Mysliwiec I like Ice Mist but it's almost identical to the trim color. I've never liked the feel of white ceilings so we've always had color on them. I've used silver strand and divine white for ceiling colors in past homes which had different color schemes. I did use ceiling bright white for a dark condo so I appreciate why everyone is recommending it.

I looked at your work before I commented on your paint selections and see the same paint ideas appearing in that work.

Well-designed homes have a consistent color story that flows effortlessly. I stand by what I commented. You don't create a color story for a home by reaching for a paint color. Paints are often selected after rugs, furnishings and accessories are selected.

If your service is organizational, then those closets used as dressing rooms should not be painted in green which affects the visual of all the clothes in the closets.

A neutral background in a closet. Doesn't have to be white, but can't be green.

BeverlyFLADeziner - good to know about green not being a good choice for closets. That's not something I would have thought of. Thank you! Since interior design is not my specialty, I'm not involved in the paint choices for my clients. I do routinely recommend changing the light fixtures or bulbs out to increase lumens and kelvins so that they can see how the clothing colors will look in daylight. Proper lighting makes a huge difference in helping someone stay organized. I have quite a few clients in new construction homes and the builder's specifications call for painting the closet the same as the bathroom or master bedroom and secondary closets the same color as the ceiling paint. So in the case of the green closet, that was the color of the "spa" master bathroom that it adjoins. But as for my own master closet, where I do have a choice, I will take your advice and paint it the ceiling shade of Snowfall which is a neutral I have fallen in love with since painting sample boards.

Just in case anyone else is following, final colors have changed. Thank you BeverlyFLADeziner for encouraging me to rethink Upward for color throughout most of house. My decorator got back in town and recommended Benjamin Moore Blue Veil which is lighter and more neutral and also the Benjamin Moore coordinating color for Stunning. I painted a large board and love it. I'll take the board to Sherwin Williams and get them to match it. Snowfall for ceilings which was the original question. Those who have seen house agree, but I respect all who weighed in with "nothing but white". Snowfall is actually listed as a white by SW. High Reflection White for doors and trim and shiplap. Silver Strand for den and bonus/office. Takes a village to paint a house... Someday I'll post photos.