Here is a review of Cold Foam. https://www.kylieminteriors.ca/9-best-white-paint-colors-sherwin-williams-designer-edition-emerald/

break fown what differences I’ll see in these colors as far as undertones?

When it comes to the theory that colors have undertones, everyone is making that up as they go. Which is why you find inconsistent information/opinions about paint colors and what undertones they allegedly possess.

In terms of factual color notations, there's no difference in hue family. Biggest difference that you'll see is in Value and Chroma.

Cold Foam is slightly lighter and brighter as indicated by its higher Value. LRV just tells you how much light a color reflects.

Cold Foam is also the more neutral color as indicated by its lower Chroma. This is the dimension that describes more or less colorful.

So, yes, comparing Chroma values validates how you're seeing Alabaster as more colorful.

Cold Foam is between Pure White and Greek Villa.

It is not as colorful as Greek Villa and is more colorful than Pure White. The difference in hue at this low of a chroma and this high luminance is negligible.

I would guess that if you mixed these two 1/2 and 1/2 you couldn't tell the difference between Cold Foam and the mixture.

@Jennifer Hogan wow thst shows how deceiving the tiny samples can be, I thought it was more colorful than greek villa. I guess if i used Cold Foam my trim would have to be the same? It’s currently extra white and I cant repaint

IMO all that info is not a replacement for poster boards as large as you can get 2 cans of the samples you like paint each board with 2 coats and see how they look in your space that IMO is the only way to choose wall color or trim color. I like all the same lighting in every space and prefer LED 4000K the lighting will have huge effect on color choice so make it simple with all the same lighting.IMO the same coloras the trim in a matte finish would be the safe answer or how about an actual color for the walls . I find a grayed green a great neutral backdrop and much more neutral than wites , beiges or grays.I love Healing Aloe BM and iuse it often for aneutral and if you want just ahint of color I cut it 25%

Patricia is right, nothing beats a large size sample to test different colors. The numbers can help you define the colors you test and tweak your choices. If a color looks to yellow or too blue it is easier to pick the next choice by examining the numbers and adjusting the choice to one that corrects the problem.

Can we ask more about your project, we only know you have extra white trim and are looking at other whites. Are you looking to paint the whole interior of your home or just a bathroom or bedroom? What other colors and finishes do you have in the home?

My preference is not to mix a cold and a warm white, but I have also seen it work. The best way to know if it will pass your inspection is to test the colors next to one another.