Yes, you would have to determine different combinations of community cards, different combinations of actions from yourself and your opponent *for each community card combination*, so it quickly becomes impossibly complex, and involves way too many probabilities that can't even be estimated. (The best way to figure this kind of thing out is surely just to use some kind of computer simulation with preprogrammed player types or something.)

In this sense, and this what was I was talking about in my other post, expectation is almost always forward-looking, so it becomes confusing when you already know the relevant information and then ask "what was my expectation in this situation?" It depends on what information is known, what information is unknown, and the likelihood of each possible state of the unknown information (quantities which are themselves almost always unknown). So, you have to state exactly what your vantage point is with respect to the unknown information.