Well...this is where I am stuck. I don't know which breaker is for the
branch circuit for the garage and bathrooms and I don't know how to
check for a defective breaker. No breaker was tripped off and they all
seem to be mechanically working.

No offense, but if you don't know how to test if a breaker is hot, then you
shouldn't be doing work like this. Really... it is about as basic as you
can get. I am sure someone will tell you how to do it, but they shouldn't
cause you need an electrician to check over whatever you have done.

BTW, not labeling your breaker box when it was working was your first
mistake; not using a GFCI (assuming for the moment that you really aren't
using one without knowing it) was your second mistake.