Is it possible to make the computer exclusively use a single faction mod and it's weapons? If so, please explain to me how. I'm looking to make it so I can do Orks vs Spacemarines or BF vs Darkstorm.

Also, is it possible to just straight remove items from a faction without causing problems with the .rtf? Like if I wanted to remove dreadnoughts, could I just remove the .ini and the corresponding folder?

Err, I recommend Buyable=0 over comment out and delete ini.

There is always the danger of inter-ini object dependence.

And for the first part, yes.

Just set up Activities.
There is a guide somewhere.

Or if you wanted it for lua, then just use some spawn code.
FortMagalar is a good example.

to prevent what mail said from confusing you, add the line
to the definition of anything you want removed, like so

all good.