The problem is, that it's really not enough to fake just a couple of members of the player class. I would need to deal with the zone (biome) finding logic, it would need a proper inventory, it would need to take care of equipment or buffs that could change spawn rates and than that doesn't even account for weird things other mods would try to do while checking for spawns... So it would pretty much have to be an actual player.
This is kind of outside the scope of this mod. I do have a different project in mind though, that this would fit into quite well. Basically, it would be yet another attempt at a sort of "multiple dimentions" library, involving multiple different server instances networked together with some form of IPC. For this I'd have to hijack to whole player management code anyway, so adding a couple fake ones probably won't be too hard.
This mod is still in the "idea" stage though, so it might not happen any time soon.
Omni Turrets (if that's what you mean) can already be rotated with wires, just like the vanilla cannons. I was sort of thinking about a machine that could invoke the use action of an item, but that is also something you need a player for. Plus I don't necessarily want people to start summoning bosses automagically.
Right clicking
on tiles doesn't directly use a player, or least the TModLoader hook doesn't use one. But, the right clicking code will usually check the player belonging to the running game instance, to get things like the held items. So this leads back to the same problem.
On the other hand, I'm not sure how necessary this would even be. I implemented extractinator support as a container. For that I ended up having to duplicate most of the code for determining to extracted item, cause again, the vanilla code needs a player. I made the DD2 crystal stand into a container.
(Out of spite, because of how unautomatable that bloody event is. ) Other than that I'm not sure what else really needs to be right clicked.