Huh, this is funny. Contrary to expectation, I'm perfectly able to use FMRS to watch parts without probe cores fall back to Kerbin. Like engines with a small fuel tank still attached to have something to put chutes on (activated simultaneously with the decoupler), or SRBs with chutes. Sometimes it even gives me the option of following chuteless debris down to its demise when I've specified that the stage should be managed by FMRS instead of Stage Recovery.
Anyway. Beautiful mod for someone who just loves to see those uncontrollable but expensive rocket parts sail back to the surface under a multitude of chutes.