If the owner is mannish, and they revolt, the rebels will be mannish 'settlers' of those lands (Woodsmen or Hillmen, depending on the settlement). If the owner is non-mannish, then the settlement will revolt back to the original faction. The type of units spawned during the rebellion depends on the faction and whether or not the province's population has been converted to mannish.
Helm's Deep. The book doesn't say so explicitly, but I think it's implied, where Gimli doesn't want to fight the Dunlendings claiming they are 'too large' - but he fights other Men just fine.