First off, this would be better suited to the Modding forum. Or would be if you hadn't asked for tips for playing as them, as well. I mentioned I'm tired, right?
Humans don't have nobles, as you said. You can easily copy-paste the relevant entries in the entity file from the dwarves to the humans.
Humans can make and use some weapons and tools Dwarves can't. You may or may not be able to make these in-game; I'm not sure. They have less variety in their gem shapes, and cannot smith some of the metals Dwarves can... including, amongst others, steel and adamantine. They also can't refine coal or make plaster powder or pearlash. It's getting late and I'm tired, so I might've missed some of the reactions, but the reactions Dwarves have that Humans don't are:
[PERMITTED_JOB:STRAND_EXTRACTOR]
[PERMITTED_REACTION:MAKE_PEARLASH]
[PERMITTED_REACTION:MAKE_PLASTER_POWDER]
[PERMITTED_REACTION:BITUMINOUS_COAL_TO_COKE]
[PERMITTED_REACTION:LIGNITE_TO_COKE]
[PERMITTED_REACTION:PIG_IRON_MAKING]
[PERMITTED_REACTION:STEEL_MAKING]
[PERMITTED_REACTION:NICKEL_SILVER_MAKING]
[PERMITTED_REACTION:BISMUTH_BRONZE_MAKING]
[PERMITTED_REACTION:ADAMANTINE_WAFERS]
For the noble positions, copy from the LAND_HOLDER_TRIGGER tags down to the [RESPONSIBILITY:MEET_WORKERS] tag of the FORCED_ADMINISTRATOR position. This'll give you all of the Dwarven nobles. You can rename the chief medical dwarf, if you don't want to call your head doctor short.
I'm not sure how well the [VARIABLE_POSITIONS:ALL] tag, which gives the Humans all of their current nobles, will co-exist with these noble positions. You might get redundant nobles, like having both a monarch and a whatever-the-Humans-call-their-ruler at the same time. Without the variable positions tag, though, you won't get the normal Human noble positions, so I'd leave it in if I were you. Hope this helped.