How to interpret reviewers comments for an accepted conference paper?
This can depend on the venue.  You didn't mention field, so I'll discuss Computer Science, with which I'm familiar.  Many conferences simply accept a paper, provide reviews, and expect "best effort" to address the comments.  They don't really enforce them.  Some have shepherds who receive an updated draft and comments on the reviews, and then "approve" the final version for the conference.  In practice, most of these are also best effort, but the effort is greater, as multiple iterations may be needed.  Only a very small number of conferences actually have shepherds who can truly stop a paper from being published -- usually this happens at those few conferences where the list of accepted papers is kept confidential until the shepherds approve.  This prevents the embarrassment of having a discrepancy between the list of papers and the final program, and I don't know that I can point at an actual instance of this being done, though I've heard rumors.

In your case, it sounds like you have a very good case for limiting your changes to those that fit, and addressing them in an extended (journal) version in the near future.  Your position here would be weakened if the conference allows extra pages after acceptance, with or without an explicit over-length fee, as some conferences do.  

The one thing to watch for would be the tone of the reviews.  If a reviewer says "I think the paper should also do X" you are free to not do X.  If it says "this paper can really only be accepted if it does X" then there is greater pressure to address it.  If in doubt, it is probably reasonable to ask the program chair(s) to weigh in.