Is it possible, using that eclipse plugin, to remote connect to a running jvm (jmx enabled) as I would do with jConsole or jProfiler, for monitoring and debugging heap, threads and so on?
Probably not according to this thread:
http://www.eclipse.org/forums/index.php/m/565234/
MAT can only trigger heap dumps from processes on the same box where the tool is running. Triggering dumps on a remote machine is not possible. Internally we also call jmap to get the dumps.