I made the mistake of tackling the question for the benefit of a beginner/intermediate lifter, since I wouldn't expect an experienced lifter of posing such questions, but my reply came across as having general application.
Agreed, see above.
Only if in the process of improving the lagging muscle during a cut other muscle groups would suffer insofar as they'd shrunk. If one managed to cut to the desired bf level while maintaining the muscle of non-lagging muscle groups and increasing the lagging one(s), it'd still be progress (as you've grudgingly 'admitted').
And this is where my above comment concerning the OP's training state and goals come into play.
If we're talking getting ready for the beach, my rationale would apply.
Not so for getting bb-contest-ready, though. I guess. I haven't dieted down to those bf levels, yet.
Bottom line: this can only be answered with more data, such as:
-lagging muscle group(s) (see my first post in this thread: improving an isolable lagging muscle group is way easier than doing so with a big muscle group)