Two jacks on a cab would be used for daisy chaining.
No dumb questions. MI equipment has been poorly documented and standardized from the beginning.
Cabs have multiple jacks normally for connecting multiple cabinets together in parallel.
Two wires from one head to one cab will share the same load as one cable would have. No additional wattage, because its the same load.
Thanks, and damn it how the heck did I forget that, that's what I did when I had the Genz Benz 410 and the Avatar 210 for half-arsed 610 set up. Man don't get old and have migrianes your brain just melts away, they should revoke my BA, and hand me a shovel and gloves.