Well its safe to say minimum there are at least 100 keys of each. I'd say most of them, like the bigger newer AAA title ones are likely 500 or less keys. Just a guess. Evil West just my guess has the most keys available.
Wow. This is a pretty awesome lineup - though, in kind of a weird way. The one game I have zero interest in is actually the most expensive, so that's nice. But I'm actually kinda torn on the others. The game I'd be most excited to play is Ghost Song, which is both the cheapest and has the highest requirement (awesome to see them actually applying stricter requirements, by the way), thereby improving the likelihood of being able to get it. But it's also a game I would buy with real money, and it's only $20. Conversely, I only "kinda" want to play Gotham Knights and Evil West, as they both seem somewhat mediocre in a way that might not hold my attention, but I wouldn't actually buy either of them until they hit the $10-15 price range, so it almost makes the most sense to buy one of them with my Alienbucks. Either way, it's great to have three games to choose from, any one of which I'd be happy with.