Pre-Dynasys MTB rear mechs work with road rear shifters. MTB front mechs have never played well with road shifters.

Shimano's CX-70 front mech has been used successfully in some cases to give enough swing for a MTB crank chainline. Otherwise, most road front mechs will not swing far enough.

You can mate a triple road front mech to a double crank...with some fiddling with the setup, it will swing far enough for the MTB double chainline.

I recently fell in love with triples, right as they are being phased out. They allow me to run much tighter cassettes for smoother intervals in the back, yet provide all the range I need. With doubles, or compact doubles, there is always some compromise or irritatingly large jump in the back in order to get the range. Some 11 speed cassettes have eliminated that, except the ones where they decided that since we have 11 speeds there is no need for front shifting at all, and they put in more irritating leaps to have pie-plate sized cogs.