[Orofacion of the Vanyar]

...Finwe, who did awaken at Cuivienen.

That's actually an assumption. I thought that Finwe, Elwe, Ingwe, etc... awoke at Cuivenen too, but found out otherwise. Tolkien never actually states these elves were the first, just the representatives of their people. Looking at the time it took the elves to be discovered and then actually make the journey west, it is very conceavable that all the "we's" could have been born on the way. Just a little info-pop.

There's no way of knowing how many were still alive.