Thanks to all. To oldhvymec4: The front speakers are indeed set to Large in the speaker set up of the Denon AVR-2807. I thus understand the crossover setting on the Denon is irrelevant and the low pass filter setting in the M&K will control. On the other hand audiorusty appears to say the low pass filter on the M&K is irrelevant-- yet it is suggested I set the low pass on the M&K to its highest available, which in this case is 100Hz. These seem contradictory.
The large/small setting in the Denon will control whether or not any bass is routed out the subwoofer output. The crossover setting in the Denon is irrelevant for the FL/FR speakers set to Large, but still relevant for any other speaker set to Small -- center, surrounds, etc. Note that crossover settings do not apply to the LFE channel as that typically covers a frequency range of 3Hz to 120Hz based on the source mix. Since you are using bass management in the Denon, you should set the low pass on the M&K to the highest setting, essentially disabling it. You don’t want to use both.