I'd stopped at .13, and returned in .19. I know I'd gotten the 'the caravan needs to leave successfully for Barony speech' bug plenty originally, but in .19 I've had no issues in the two new forts I've run - the liason happily offers me the option while the traders are still at the depot (haven't tried with the caravan dead, though), and it becomes official as soon as the Liason makes it off the map alive. Promotion to a county and a duchy is just an extra screen near the start of the Liason conversation for that year, mentioning the impending change, and it happens as soon as the Liason makes it off the map alive - there's no 'choice' or 'acceptance' involved, mere notification by the Liason.
I haven't seen a Dungeon Master or a Hammerer in a long time, since when they were generally labelled 'bugged'. I'd tried various voodoo in pre-.13 versions to get a Dungeon Master with no success, and haven't seen one yet in .19 or .21 either.
In the earlier (pre-.13) versions, I've gotten the monarchs as well. They were generally widows/widowers of a nearly-dead civilization, however, so they came with virtually nothing for an entourage. Last time I had a for large enough for a Mayor was during the multiple-mayors bug, so I got too many of that noble, rather than too few :p
The main two abnormalities of my forts are small size (~40 dwarves usually; my two .19 forts have had ~35 dwarves) and no Justice system (I never appoint a Captain of the Guard, so that whole side of things never kicks in aside from Nobles being unhappy about delayed punishments). The only mod was a change to the goblin civ, lowering their min population for sieges so I could still be besieged with such small forts.
So, essentially, in my experience the appointed nobility (expedition leader, etc), the promoted nobility (barony and beyond), and the monarch works fine, but the Dungeon Master, Hammerer, and Tax Collector seem unacquireable in vanilla at this point.