what rpm is this Actuator?

The short answer is “adequate to respond to the damper shutter demands” and I don’t mean to sound like a smart a__. The motor turns quickly but, because it operates through a gear train, it’s effect is much slower, but with greater torque (leverage). So the answer depends on which end of the process you measure rpm. I would advise against using this unit for an application for which it is not intended. Hope this helps more than angers. Trying to help

Will this work to replace the M847D1012?

I replaced two M847D1004 models so can't say about the 1012.

direct replacement for M847D1004 ?

Not sure. I replaced by appearance and it worked. May not be the same for you. Return of electronic parts may not be allowed so it is probably not economical to speculate.

Will this replace Hanson Corporations 135-6-20 (645 1543)?

Well, those numbers dont mean anything to us, and hansen makes lots of motors, but if you are referring to the complete hansen motor that looks like ours in the pic, but maybe withyellow wires, as used by Jackson Systems and others, then yes it will work.