Will Genesis 2 be available right after release?
As soon as Steam puts it as public.
But if prior steam launches of ARK are any indication, it's going to be a cluster fuck, buggy as hell, and cause massive crashes and corruptions world wide for all companies.
you'll have to decide if you want to lose people in your community for not having it on day of launch, or losing people in your community beacuse of WildCard's shitty code and crashes.
As a rule of thumb, I don't put up a server on a new map until it's been out for 5-6 patches (usually 10-14 days.)