If an account is closed but with a balance and being managed by a DMP, do the comments about DMP impact FICO at all?
Not at all. IMHO I don't even think lenders care based on my experience with DMP.
Comments in and of themselves don't impact Fico scores. This goes for both closed and open accounts. Comments are not part of Fico scoring criteria, though they can be seen by a human being and lead to questions being asked.