As far as the midi goes, I would connect the Motif to the Motu128 in the 1st midi channel...(connect both in and out)
Then connect the motif to the Motu128 to the 2nd midi channel (both in and out)
This way you have connected both the Motif and MPC through midi and audio...
I hope I didnt confuse you, if I did, just ask me to clear up what I confused you on...
HOLLA
CATRON/TheReturn
I think bro. Catron meant to connect the MPC to midi in and out on the MOTU interface. I agree with that. It would allow you to use either the Motif or MPC as a controller. If you sequence externally and send the midi to your VST instruments, you may have some latency issues. Some adjustments to your sound card settings might correct the problem.