Sounds like what you want is a tower defense game. Keep that in mind when you shop for games in the future.

This game just isn't made for that sort of thing. All events are RNG so you could have all these fancy base defenses and never get a raid event.

Also no need to leave guards at other bases as enemies will not attack if you are not there... the area is just suspended until a player enter the area and "spawns" it in.

Since we are dead heros sent here on a mission I also believe having others here as "support" is totally opposite of the world building the devs have done.

I wouldn't care if they added a tower defense mode, but I think they are more focused at this time on finishing the game and making it right before adding in extra features.

The friendly NPC thing sounds uncool to me though. Basically you just want slaves.

You also already have things like spikes, lox and wolves for defense.
https://steamcommunity.com/sharedfiles/filedetails/?id=2493990573
https://steamcommunity.com/sharedfiles/filedetails/?id=2446192190