what would a 'memory bound' kernel be?
Memory bound refers to a general case where a code is limited by memory access, ie. it includes codes that are latency bound and codes that are bandwidth bound. You've defined pretty much all the other terms correctly.
Is there ambiguity, and if yes, should we limit the conversation to the three above terms?
I don't think there's much ambiguity (you've clearly demarcated 3 of the 4 terms, anyway), and you're not going to impose order on the world in a SO question/answer.