The 788 has 6 analog inputs,...
which is the 4 "main" inputs A-D, plus two "Aux" inputs, on 1/4" unbalanced jacks, running -10dbU signal level. This would require, in most cases, a mixer as front-end to feed signal to the 788's Aux inputs.
By my reading of the MR8 manual, the MR8's Stereo-Out-L/R jacks output the L/R-buss signals, and so the MR8 may be used as a "front-end" mixer to the 788's Aux Inputs, in the scenario you illustrate. I think this is the answer you were looking for.
Dude, you were not clear, at all, but at what point did I become a condescending fuck?
You obviously don't have a clue about home recording, or recording gear, at all, or of the obvious fact that you shouldn't come shooting from the hip out of the Newbie column, calling people names! You won't last long on this board, if you do.
You called me unkind names, and I still helped you, but I doubt you're bright enough to put those two machines together for any use, despite the help of well intentioned members.
You picked the wrong guy on this board to piss off!
Any more questions, then try to be clear, you dumb assed motherfucker!