Do players on the practice squad get Super Bowl bonus?

Yes.

The NFL pays for 150 rings to be distributed by the Super Bowl winning team. The team may distribute them however they wish. Should the team decide they want to give out more than 150 rings, they must pay for the cost of the rings after the 150.

So not only do practice squad members get rings but ball boys, trainers, secretaries, among others, probably get one also.