My MIDI hub is a MOTU midi express 128:

https://www.amazon.com/MOTU-MIDI-EXPRESS-128-Express/dp/B0002J1PNK/ref=sr_1_1_sspa?ie=UTF8&qid=1546546387&sr=8-1-spons&keywords=midi+express+128&psc=1

I drag and drop my BiaB files into my DAW, Studio One Pro 4, then assign each track to a MIDI sound. Sometimes it is a hard synth but most of the time it is a soft synth.

As far as mixing audio I strongly suggest one uses the mixer that comes with your DAW and not an external mixer. This may mean that you have to purchase an audio interface. I have a Roland OctaCapture.

Each output goes on a separate track in my DAW. Using the DAW's mixer I can add effects to any track as well as adding busses. Much more convenient than using an external mixer, at least for me. YMMV

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware