I tried to solve the third question in the pi-day pizzahut contest, but I'm not sure i understood the puzzle correctly, so I am interested in lg community thoughts about it:
I am not sure I understand your point about pairs : for me a pair is any two rings, so for the pairs to be undistinguishable, all the rings must be links two by two, otherwise I can distinguish an unlinked pair from a linked one. Do you understand a pair to be only two rings that are linked together?
I agree that the question is ambiguous. One interpretation of the first statement is that the automorphism group of the link acts transitively on the pairs; another is that either every pair is linked or every pair is unlinked. Conway is probably happy for people to just get confused by the ambiguity. You could ask on math.stackexchange, you might get more of a response there?