normally i would but there will e only 1 set of AUD mics and he wants to run AUD only. I figured i would do this as an experiment. I guess if i just set the bit depth to what he does I won't run into an issue
Once the AUD UA-5 converts D>A to output via the RCAs, the AUD UA-5's bit-depth and sample rate becomes a non-issue for you. You can set your SBD/mix UA-5's bit-depth and sample rate to whatever you like, regardless of the bit-depth and sample rate on the AUD UA-5.
In other words, the AUD UA-5's bit-depth and sample rate will impact the quality of the analog signal you're receiving out of the RCAs (audible or not, I don't know), but you yourself can run whatever bit-depth and sample rate you want on your SBD/mix UA-5.