I really like Everest and what the team is trying to accomplish.Is whitelist already open?Can we sign up?

Whitelist for what? Pre sale, sale, open beta?

I don't think there are whitelists for private sales?

You are right,there is no Whitelist for Everest

Why is whitelist used at all,whats the point of that?

To allow people to show their interest as to know who would like to invest in your project

And to reserve a spot in queue so you can invest.

But what is the purpose of reserving a spot if they dont know how much youre gping to invest?

I personally prefer first come first serve kind of system.

That would make the most sense. If you find out about the project early on then you can invest. If it is much later then you miss your chance.