Depending on the device you can run in WDM mode while recording and use 2 ( or more?) audio interfaces. WDM is not the greatest for latency so best to then swicth back to ASIO for overdubs and working with soft synths.
I did a loop back test and found that in WDM mode my tracks where out of sync. This will vary from device to device.
My Scarlett does not have WDM drivers so I can't use it but my Tascam us1641 runs fine on WDM.
I think the WDM driver needs to be available via windows and not every device has it.
And the good news is Yamaha mixers uses Stienberg drivers which are good to go in WDM mode. At least it worked for me when I tested it using a Yamaha analogue mixer my band bought and paired it up with my Tascam. The board only had the stereo USB output but it gave me 2 more channels with the board mix on my live recordings.
So a solution for you would be a Tascam 16x08 which is the new version of the us1641 and us1800, only $300, good drivers,, good pre amps and an extra 16 channels.
http://www.sweetwater.com/store/detail/US16x08 They actually only have 14 analogue inputs but you could use the SPDIF via the Yamaha 01v as well. That is still how I connect my 01v to my system,, SPDIF
My Tascam is a great interface for recording a band, and even better with the new drivers Tascam took the trouble to produce. And the price hasn't change, I paid the same $299 for mine at least 8 years ago.