An average amount of skill, but I think "getting used to it" should be easy. We went over the juice with this, and I think a quick tutorial would be more than enough to teach you about the game.
Building, like I said is a hard part to put into reference, not only due to its implitations, but how you should and how much you should be able to do. If possible keeping it like DvZ would be perfect.
45~ mins with a standard deviation of 10 minuites? That would mean 35 mins is one away, and 25 mins is very very hard to acomplish, while 55-1:05 is possible. The 25 mins is a bit low so boost it I guess maybe.
Players is always a big problem with indie like games. If rob were to talk about it/promote it? Easy to get lots. I'd say 50-60 per game would be optimal, with maybe event like large maps having battle royale sized 100 players.
I feel like this is the kind of game you can trickle content into to keep it alive, maybe even using a season pass to gate newer weapons in loadouts? Eh doesn't sound good. I feel like having a limit of 3-4 heroes a game is good. So maybe a rotation of 5 heroes at first sounds about right? As for weapons, I don't think at the start more than like three are needed. A basic one, a more "damage centric" one, and maybe something special, then slowly trickle more in. Same with items. Mobs, are different. I feel like putting in all the DvZ ones at the start other than autistic ones like "swammies" and maybe rats would be good.