• Can I add the mod mid-game?: Yes you can. It will remove any weapons, ammo, turrets, etc. from the game (including blueprints, recipes, etc.), kill all existing biters, and prevent them from spawning. When using Pacifist with other mods, I recommend that you create a backup of your save file though.
• Is this compatible with my favorite overhaul mod?: There is a compatibility list at the end of the mod information tab (or README.md on GitHub). IF your mod is not listed there, you'll have to check. If that overhaul mod is not too complex and does not add nonmilitary recipes with military ingredients, there's a good chance that it might just work. In any case, please let me know in the discussions, so I can add tests and add it to the list.
• It breaks when I combine this with mod X: This is bound to happen, as Pacifist basically removes "everything that's a gun", "everything that is ammo", and so on. Mods that rely on their custom guns, ammo turrets, etc. might become unusable or prevent the game from starting. Please report any incompatibility in the discussions here or on GitHub
• Can you add grenades back, please? I want them for tre removal: I have decided against that, including another option in the map settings. A grenade, however its intended use, is a weapon and should not exist in Pacifist. Modified grenades that only remove trees would be an option, but there already is the Explosive Termites mod.