It will make things look bigger, not smaller.

Right now you need to decide if you want to go cool or warm with your colors. You mentioned you want beige in the stone, which would go with your cabinets, but not with your current flooring or paint colors. Right now that blue paint in the kitchen, and the lighting, is making your cabinets look yellow rather than ivory.

As for tile color, I always suggest a timeless look which would be a natural medium color. Skip anything gray washed, too trendy and will look dated in 2 years.

I used the same flooring throughout my very small home, and I used vinyl planks which looks like wood, even in the bathroom and kitchen. So, it was seamless (no transition strips into the bedroom and bathrooms etc). It made the home look much larger. Also, you can consider the angle you will have the flooring installed. I followed the lines of the wall, but you can also do it at an angle. You might use 30% more flooring this way, but it is more interesting to the eye and can help make your home look larger. Good luck with your home!

I think you're mostly in the cool camp... "traces" of warm won't matter too much.

I absolutely LOVE the idea of laying the tile on the diagonal. I would love it more if you used hardwood, but that's my own preference and not yours.

On my monitor your cabs look white (not a stark cool white, but a white nonetheless) so they would go with almost anything...with the exception of a totally cool counter (carrara for example because that's VERY cool and might make your cabs look dirty.)

I'm loving soapstone at the moment...look how pretty with beadboard backsplash:

Do you have samples of what you're considering? Will you do a backsplash?

Using the same floor will make it look larger, provided the color is not dark. Medium to light tone floor if you want the home to be light and bright.

We put LVT throughout our home, and it is gorgeous. Not trying to talk you into LVT, that's a personal choice, but the same floor throughout your home will indeed make it look larger.

My recommendation is to make sure the subfloor is level to eliminate the need for transitions. Our installer nailed down plywood where carpet was taken out.