I see a number of problems with this.
First, according to the resource system, territory contiguous with the main nation is not a colony, but an expansion, and thus does not bring any new resources. Now, I know the way around that is to propose that you annexed the tribal territory first, and then the area around it, technically making the tribal area a colony, and the second annexation an expansion. This is a loophole that must be corrected.
Second, a "semi-autonomous nation" is a protectorate, and unless you assert full sovereignty over the area, then it can't be considered annexed, and you shouldn't get access to the resouces. If you want to claim that it's annexed, but that you let local government proceed, that's fine, but "semi-autonomous nation" doesn't sit well.
Third, the resistance factor's disturbing me. Are you going to have them acquiesce to Bustian domination, or are they eventually going to fight for national sovereignty? Remember, you let everybody carry a weapon
If there's no further resistance, that's not going to sit well with me.
Fourth, you and Myroria are starting a land-grabbing spree that I really don't want to see extended to the rest of RP. Soon the map's going to end up looking like the Lex map where every other nation is a colony. Not only is it boring, it encourages large-scale war RP, domination, and other bad things that, while they do exist in the real world, form a horrible RP environment, especially for people who are just trying to join in.
Fifth, and this is related to the previous point, where does it end? Once the land-grabs begin, they won't end unless somebody puts a stop to it IC, and that won't happen because all the strong nations are grabbing land.
Sixth, I'm hurt that you didn't ask me to RP the natives. Not really, but I thought it would be funny to say.