What you're saying sounds reasonable. I don't know how big the tabs are, but I would try to get by with the fewest number of plug welds as possible. I would start with just one. There can't be much stress placed on the bracket. Be sure to clean the spot on the motor casing down to bright metal before you weld.

Good luck.

When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
-Unknown-