I guess I should wade in here since I've actually done what you're asking about. I bought 8 RS-880 cabinets a few years ago. Half of them had the woofers replaced by B&C 15HPL76, and the other half had the original Community woofers -- though they were so brittle that they cracked when touched.
The B&C drivers worked well, but I was reluctant to load the same drivers into the other 4 cabinets because the driver frame is just slightly too large for the fiberglass lip that it mounts to in the cabinet. The four which had been switched over, had that lip removed, and I really wasn't satisfied with the resulting fit of the drivers, or in the way they were mounted.
I ended up loading the other cabinets with Eminence Kappalite 3015s, and have been satisfied with the results -- and they fit in the cabinets without modification. The most divergent specs are the Qe and Vas, while others are closer.
Subsequently I replaced the B&C drivers with more of the 3015s, as the B&C woofers were also getting a bit long in the tooth, so now all 8 are loaded identically.
The crossovers were in various states of disrepair, so I run the boxes biamped, with my own crossover between the mid and high horns. All the highs have been switched over to B&C DE250, which is a driver I really like. So at the moment, the only stock driver is the M200 midrange.