I made a Minor Tribe resource pop up every time you get a money goody hut (set it as 'default money resource'), but I have no idea what to have it do. I've had the idea of Native Scout units and Slave units, but the Native Scouts would make being Expansionist pointless and I think the Slave unit would unbalance the game (same as a worker but without population cost).
I guess I'm more inclined to do the Slave unit, bu if anyone has any better suggestions, I'm open to them, and would probably prefer them.

I'm also having trouble with diplomacy. I made 2 new civilizations (Mali and Incas), but when you talk to them, the first text that pops up (like "Hi" or "What's up") is blank. Anyone know how to fix that?

AHHH so thats what happens when you change the default resource from Gold to a resource. I usually use my tribal resource for hidden nationality "mercenary" units I created.

About diplomacy: you have to edit diplomacy.txt I believe. There is an editor for such tasks, look in the utility programs forum.