I am also looking for this information. The compatability matrix is WAY behind.
Will ACS v5.2 integrate with CSM 4.2? At this point I think I'm only asking for the information - not sure we're interested in integrating them again...
We had an integration between ACS 3.x with CSM 3.1 and it was a nightmare to try and juggle the interoperbility. You couldn't upgrade one without the other in many cases.
The better solution would be to include the "per-NDG" type rights in CSM itself, like what's been done to LMS 4.