The power is shut off in the house... It is being remodeled. And, I
misspoke about grounding the breaker in the panel, otherwise I was
looking for alternate ways of wiring up the bath and updating the wires
to the bath.

With 60 AMPS coming in and currently 15 + 15 Amps in the three rooms,
adding a 15 or 20 Amp breaker to the box won't affect the main breaker
in terms of tripping. The most going thru the three rooms would be 50
AMPs if a 20 AMP breaker and 12/2 was added to the bathroom.