whoa cowboy, that's a lot of material
lemme do a quick scope overview of how feasible this all is
-resting belly against the red queen's head: i always thought girls pressing bellies together was really hot, so I've basically already decided on drawing a belly comparison victory screen. however there is room for a different victory screen when you beat the opponent by a large margin, and I'm thinking that I'll draw the blue queen in the background pressing her belly and boobs against glass, and the red queen stuck between the blue queen's belly and the glass, which, in a way, is kinda what you described
-arcade would probably feature a smaller map and be renamed to "skirmish". there would be no need to make this unlockable, it would be available from the start menu (but would not unlock anything)
-"hardcore" is already associated with other game mechanics, most prominently permadeath which is not what you're proposing. the idea is fine but i'm not using that name
-bees: my turn system actually supports up to 5 teams, so I can definitely fit bees. I'll start by experimenting with a beehive tile, basically working like a non-depleting honey basket that can be attacked to provide more honey than a regular basket, but also spawns a bee every time it's attacked. I can also do queen bees, but most likely not with their own hand-drawn and animated avatars, they're just going to be boss units that hit hard and drop a ton of honey when killed. either way, the bee faction is probably not going to be an actual team that can win, just a resource guardian designed to forestall the inevitable
-multiple ant queens: major code rewrite required, don't count on it
-unit taking up more than 1 tile: theoretically possible but not really worth it imo, especially because the size is coming from the insect abdomen which is not (intended to be) the fetish part of the video game. it would also take an even more extensive code rewrite than multiple queens
-drones: MALES IN MY LESBIAN BELLY FETISH GAME (not this time but thanks anyway)