which one of these interesting savages was which.

Whilst I agree that the question was not presented very crisply (and. let us remember, milum was not actually setting us the problem at the time) I contend that the most reasonable assumption is that, as you are to find which one is which, that the choice is narrowed to two individuals, one of each tribe.
Had it been to find out which of the congregation of x Indians was which, the conundrum would have been, which of these interesting savages was which.
(with the "one" removed from the sentence.)

The task would not have been simple, and certainly not possible with just one question, I think. (The identical question, many times, is not the same thing at all!)

However, I do agree that it would have been better had I re-stated the question in totally unambiguous terms, (although that would have deprived Faldage and I a longish and very interesting conversation!)

I ought to add my especial thanks to Iris, for starting this thread in the first place.

STOP PRESS

dxb came in with the correct answer (also on his second attempt), about ½ hour after the deadline.
Hono(u)rable mention in despatches!