Ok, 1 are you still working on this? Please by god do. 2 It may be a while because it is a big map but make the doors open one way so players dont get killed by being trapped by bullcrap doors. 3 add a way to get hp back like a custom item that you use for Hp back.
IMO the ability to choose your ""spawn"" location seems integral to the BR formula, so I'd want to make sure that's set up if I were you, not hard at all.
Are you sure you want to go with an outdoor setting? Since you express a desire to focus on CQB it seems like an odd choice, perhaps only made as such because your source material dictates it.
As for the map size itself.. Sure, you could scale it down to as small as you see fit, but doesn't that very much undermine the concept you're working towards? At that point it's just deathmatch without respawns.