Which hand do I use to strum?

Kimura Lock for submission and Strong Arm Chop for non-submission, in my opinion.

You could look at your hand and then copy what you see. You could also put something like paint on your hand, brushing it on gently, to make the lines...

Your swing will be easier if your hands touch each other on the bat handle.

If you're right-handed, use your right hand to hold your teacup, and vice versa.

The hand that is closer to the field when running.