Hamish is the Anglo spelling of Sheumais, Scottish version of
James.
Alpin is the Anglo version of
Ailpein which has not obvious Gaelic etymology and is widely assumed to be Pictish.
Mungho should be
Mungo (extra letters does not authentic Gaelic make) and
Aonghas is simply *modern* Gaelic of
Angus (the desire to make the simple complex is widely shared in the Western world) so either seems to fit in nicely.
Devon