You know - only two years ago, when MIR finally found its recent form, the idea of running it side-by-side with a full-blown DAW on the same computer was a bit ... uhm ... adventurous. ๐ MIR was always meant to be used as stand-alone application on a dedicated computer.
What you _could_ do now (without spending too much money) is to get one of those inexpensive USB2-stereo-interfaces*) for the exclusive use of MIR. Connect its digital outs to the MR816s, and you're done.
*) look for 64-bit ASIO drivers and latency numbers that support powers of 2 (i.e. 64 samples, 128, 256 etc.)
[...] Will MIR pro have some sort of routing into the host sequencer, so it does not need to access the driver itself?
If everything works out as planned - yes.
/Dietz - Vienna Symphonic Library