That's because you said you had a good system now, so I assume you are reasonably happy about what you have. As such, I would focus on getting the best out of what you have already, by using the RX-A880 to power the left and right for critical music listening.
The AVR has better specs on paper than the XLS 1002. It is less powerful, but even if the RP-260F dips to 4 or 3 ohms at a couple points in the 30-100 Hz range, the RX-A880 should have no trouble pushing over 100 W into such loads. Yamaha rated its dynamic power 240 W into 2 ohms, two channel driven. That's obviously just for short duration, and it would do a lot less, say 1/2 to 1/4 of that for longer duration but that's more than enough for the RP-260F especially if you set the crossovers for the L/R to 80 Hz. So choosing the AVR over the Crown is a matter of quality over quantity.
The reason I suggested to use the more powerful XLS 1002 to power the center channel is simple. For action movies, the center channel will most likely draw more power from the amp than the L/R, not more than L+R, but more than L, or R on average.
The APA150 has the lowest audio specs of the 3, and that's why I would use them to drive the surround speakers.
It may not make any audible difference, but it costs you nothing to try.