I took a quick look through the mocks and my gut tells me it's a little too ambitious for a first version. Focus on one problem real people have that other social platforms don't solve well, and do it well. Cloning facebook's featureset does not a social network make.
It's not a first version, I've been developing this for a few years now, there's around 50 sites running the software, and our beta site has around 600 users.
It's probably still too ambitious, though, but that's why it's fun. :)
