1. Ask alien 1, "If I asked you 'Are you Random?' in your current mental state, would you say 'umpa'?"
If 1 answers 'umpa', then 1 is Random:
2a. Ask alien 2, "If I asked you 'Are you True?', would you say 'umpa'?"
If 2 answers 'umpa', then 2 is True and 3 is False.
If 2 answers 'lumpa', then 2 is False and 3 is True. In both cases, the puzzle is solved.
If 1 answers 'lumpa', then 1 is not Random:
2b. Ask alien 1, "If I asked you 'Are you True?', would you say 'umpa'?"
If 1 answers 'umpa', then 1 is True.
If 1 answers 'lumpa', then 1 is False.
3. Ask alien 1, "If I asked you 'Is 2 Random?', would you say 'umpa'?"
If 1 answers 'umpa', then 2 is Random, and 3 is the opposite of 1.
If 1 answers 'lumpa', then 3 is Random, and 2 is the opposite of 1.
1 = False
2 = Truth
3 = Random