White for what? Ceiling or trim or both?

Yes, I meant trim and ceilings.

Do we just go with basic "white", or are there specific guidelines when choosing white?

There are. DE's White DEW380 works well with Cloud - pretty color choice, btw.

Also, regarding finish, it seems eggshell is very common. My contractor recommends using the VersaSatin paint which has a "satin" finish. Are these both similar?

They are not similar. Versa has a typical level of shiny for a satin. Every brand's gloss levels are different which makes it really hard to have a conversation about finishes unless you have samples in front of you, but this one fits what most people expect a satin to look like - IMHO.

DE's eggshell is not shiny but the "hand" still has some slip.

Eggshell on the wall.

Satin in closets, on doors and trim.

Flat on the ceiling.

Finally, what accent color goes well? I'm thinking Ice Gray, but we're currently out of town for a week and are unable to put the color samples on the wall.

Nope. Ice Gray belongs to the Yellow-Red hue family. Cloud belongs to the Green-Yellow hue family. It wouldn't be awful, but you can do better.

And unless there's a reason or a need to apply an accent color, you probably don't even need one.

Also, near neutrals like Ice Gray that belong to the YR hue family can shift and look quite purple in certain qualities of light. You don't want to use a color like this one unless you can test and sample and test and sample some more in the space.