With their requirements, it likely has to be a fork at least. It's not like any coin is perfect for what they want. I think Steem is actually pretty close... So they will get some exposure from whatever community they fork from for being forked from that coin, but it may be limited. There are Steem forks that practically no one on here knows about except the most diehard.

But an entire year, if they get a kickass developer team, will be plenty of time to make something more than workable. If they use something close enough, maybe the majority of their time will be spent on the site.

I think what they choose will greatly influence what happens though. Anything could probably be adapted given enough time, but blockchain devs are at a premium right now. If they made a huge mistake and picked the wrong blockchain to start with and got too far in the development to easily switch, it might be a total flop.

I'm kinda rooting for them to pick Steem, because we need more diversified devs working on the coin and not just Steemit.