I may be wrong here, but I think there is something about not getting access to the trade liaison until you've appointed a baron.
Also, as nobles go, barons can be made quite benign. The trick is to make sure the dorf (or other citizen) you appoint doesn't have any preference for items that can be constructed (thus, materials, shapes, animals, food/drink etc. are fine, but crutches and scepters are a pain). A noble with no item preferences will not issue any mandates: they can still make *demands* but failing to meet their sometimes impossible, demands (e.g. a brass bed), will not result in the punishment and possible death of a random, probably valuable, citizen failing to meet mandates does. The noble will just be unhappy about not having demands met You can also try not to enable the injustice system, but that has a tendency to turn itself on when you need more militia.
You can keep the monarch at bay by making sure you don't donate anything to the mountainhome (but you can still get saddled with a random citizen becoming the new monarch when the old one bites the bullet. A healthy dwarven civ reduces the risk of that happening, but the only sure way is to play a civ that actually dead (should be dead as a door nail according to all logic is NOT sufficient, there's a bug that causes them to die as they should. A civ is actually dead if the civ screen, when viewed immediately after embark, is completely blank, i.e. not even your own civ on it).