For lowest latency, use the i2M with the BR80. You can use the i2M for MIDI and the BR80 for audio, then there is no sample-rate conversion required (as is used in ASIO4All, and the i2M ASIO driver) so no extra latency step.
All you need to do is get a Y-cable and connect the input to both the BR80 and the i2M. The input impedance of the i2M is very high, so you won't notice any difference in sound quality doing this.
(With the sonuus G2M, this is exactly what you do when you want to also use the audio signal. The "true" connection is wired just like a Y-cable.)