#2
If the ohms match and the cabinet is rated at greater than 50W, yes.
Epi Explorer
Squier Vintage Modified Tele

Dunlop Crybaby (modded)
TC Polytune
Marshall ED-1
Vexter Box of Rock
Harmonic Jerkulator (home made)
Boss CE-3
Line6 Echo Park

Modified Traynor YCV40
Fender Super Champ XD
#4
yes.

you can hook any type of combo (you don't have to make a thread for each one) that has a speaker out jack, to any cab. (ohms and watts considered).

generally, try to use a cab that can handle double the wattage of the combo you are using.
#5
Since the JCM is a mono head, you'd wanna use the cab mono.
Epi Explorer
Squier Vintage Modified Tele

Dunlop Crybaby (modded)
TC Polytune
Marshall ED-1
Vexter Box of Rock
Harmonic Jerkulator (home made)
Boss CE-3
Line6 Echo Park

Modified Traynor YCV40
Fender Super Champ XD
#6
Thanks guys, one last question, would i need a Split speaker cable to run the cab?

http://www.thomann.de/gb/media_bdbviewer_AR_252107.html?image=6

As the rear input looks like that

My marshall has two speaker outs, 50W rms, with a 8 or 4(16 selector)
the speaker in there is 8 Ohm, so i would be able to run the cab but not the amps speaker?