Hey Kips, MikeB has same set up (MP1, GMaj, FCB1011), so he can help you with the more complex possibilities (the FCB is a many splendid thing but Mike's got it worked out). Basically (using 5 pin midi cables) you plug the FCB midi out into MP1 midi in and either MP1 midi out or MP1 midi through into the GMaj midi in. When you send a midi patch change from FCB (step on a button) it goes to MP1 and also GMaj and they both change to that patch number. The difference between MP1 midi out and through is you can configure the MP1 to send out a different number than what it receives (midi out, but default is 1-1 mapping), midi through just goes straight through and is the same number the MP1 midi in received.
Good poweramp option is Carvin DCM200 (1 RU, very lite ~1.5 kg IIRC) very clean and transparent (which is what you want for MP1/2). There's quite a few posts here on the topic, RabbidGerry has been checking out another 1RU unit that also looked good. Don't go tube poweramp unless you are ok with the weight, my Carvin TS100 (great amp) but very heavy (nearly as heavy as Dante's car LOL). For your cab, depending what it is, how many speakers and their power handling capacity, you can wire it in stereo like I did with my old Yamaha quad box. Not "quite" as good as 2 separate cabs but good enough. Thats the cab I used on Reverends Rock in the MP1 clips posts. I currently use an ADA slant split stack (2 x 12" Celetion 70w speakers) wired in stereo, works a treat with the 50w per side TS100. I also have 2 other split stacks with 90w Boogie Celetions in them, which I used with ADA B200s (also a great amp for MP1/2, 2RU again clean transparent SS amp). But more than I need to lug around for now so they tend to stay at home.