I've been wanting a TTT minigame for Minecraft for years, I've tried countless times with command blocks but my skill with them isn't the Best.
On the TTT workshop (On Steam), people have made mods for Gmod TTT such as TTT2 and Custom Roles for TTT. If I understood it correctly its possible that you assign base roles I.e Innocent and Traitor to everyone (So depending on players 2 or 3 players are given Traitor baserole and everyone else the Innocent baserole) then you can assign Secondary roles to the Baseroles I.e Detective and any other new roles you want. If you like this idea you can look at TTT2 roles here
If you add custom roles it could be a good idea to be able to activate and Deactivate roles so if someone would like to only have the 3 basic role they could or you could add role presets so basically different game mode with different roles.
3rd party roles that win on there own or change roles are often given to the Innocent baserole
On the TTT workshop (On Steam), people have made mods for Gmod TTT such as TTT2 and Custom Roles for TTT. If I understood it correctly its possible that you assign base roles I.e Innocent and Traitor to everyone (So depending on players 2 or 3 players are given Traitor baserole and everyone else the Innocent baserole) then you can assign Secondary roles to the Baseroles I.e Detective and any other new roles you want. If you like this idea you can look at TTT2 roles here
If you add custom roles it could be a good idea to be able to activate and Deactivate roles so if someone would like to only have the 3 basic role they could or you could add role presets so basically different game mode with different roles.
3rd party roles that win on there own or change roles are often given to the Innocent baserole