1. Yes.
2. That ebay price if pretty good.
3. The wheelset comes with all the parts you need. Just remove your old wheels and install these. Done. I'm not positive but you can probably use the cog and lockring from your pista. You just have to make sure all the threadings are the same. If not then you'll not a cog and locking with threading that matches the Formula hubs.

On a side note, I think those lower profile Alex rims look much better than the V's. Everyone is riding around on V's these days.

Oh and I won't be the only one to tell you this, but if you're riding that thing fixed, invest in some kind of foot retention.