If you haven't got a sub then I'm not sure if your crossover setting means anything. In any case, if you aren't running a sub then you'll need to run your fronts at least as large and the LFE channel should be directed to them so long as the sub setting in the AVR is set to 'Off'.
FWIW leave your LFE set ot 120Hz for when you do get a sub since the LFE channel can output up to 120Hz so setting it lower will just cut it off (and it doesn't get redirected anywhere else, you just lose any signal above whatever you set it to if not 120Hz).
The 686 should be capable of reaching 80Hz without issues so I'd try it set to 80Hz rather than 90Hz otherwise you're needlessly redirecting directional signal (ie above 80Hz) to the front speakers which will reduce the surround effect.
"Don't believe everything you read on the internet". William Shakespeare 1615