I made the same kind of alterations for my modded goblin games.
It just needs a mundane set of nobles to get started and interactions. Expedition leaders for example will recieve diplomats like liasons if they are set (though the text is unalterable and you will still be greeted by the dwarven greeting)
Naming and what each noble does is up to you, however applying certain specific tags may incur crashes (druid relgion responsibility tags for instance and mayoral elections, monarchs should be fine but without a mayor to progress to trigger the monarchs arrival, i do not think they function in the same capacity because of how they are hardcoded therefore avoiding a potential crash.)
Naturally much like the current foundation of nobles for most roles you only NEED one specialist (book-keeper/trader) but you can have more for instance if you need more designated teams of traders on hand swapping out here and there rather than reassigning your best all the time. Though i am unsure if two or more book keepers have any effect to counterbalancing poor office quality & record keeping progression by working in individual offices or if only one is logged. (For RP purposes its all kosher to have more for RP purposes)
Some are mix and match; A sheriff renamed a Human "Baron/Baroness or even a Doge/Dogess" could also be a sheriff and a militia commander simultaneously from embark if the correct responsibilities are passed, however it may not always swing in your favour and elective leadership or roles could lead to disproportion when the mantle is being passed around constantly. The military can also be composed of potentially infinite amounts of "Knights" or militia bands with configuration or a strict number depending on how you tweak it.
Typically you will want some kind of expedition leader, no matter how obtuse or laid back they are to help build up the network of nobles through assignment (the expedition leader assigns the militia commander)
Generals and off site nobles are much less important unless you have a monarch in which then they will be pivotal to doing things in world generation. In the case that you win a world gen battle against a settlement, having a conquered site noble will let it merge in with your own rather than razing it in the instance that it is a likable site.