Chris

You should be able to skip the pre amp (your multi-effects should also have a preamp). You can go direct out of the ME board and go eitgher straight to your speaker or even straight to your mixing board.

My "normal" stage set up when I use my amp and pedals is

Guitar -> pedal board -> Orange TH 30

I mic the amp and then send that mic to the mixing board. I then have my own wedge as a monitor and then of course FOH.

With the ME board, I simply did

guitar -> ME board -> mixing board