Sollux didn't escape the Vast Glub, Feferi had to revive one of his dream selves for him to be able to enter the medium.
Yes, Sollux didn’t escape it and he had to be revived by Feferi.
Yes, Sollux didn’t escape it and he had to be revived by Feferi.
No, we’ve never seen what happens after players enter the new universe.