The BeeQuiet will pretty much rule out remote attenuation options, but you can add an aftermarket remote attenuator reasonably easily (be sure to power it from its own supply).
For HT bypass, one easy option would be to substitute RCA jacks for the XLR outputs, then put in a 4PDT toggle switch by the outputs. In one position, the output of the preamp gets sent to the output jacks, in the other, the RCA jacks you've added are connected to the stock output jacks - bypassing the preamp entirely.
-PB