All bathroom outlets are dead
Perhaps you can rent, or borrow at a tool library, a proper de-energized circuit tracer.  Unfortunately the inexpensive "circuit breaker finders" only work on energized circuits, though you could use one of those in a process of elimination, and to build up a circuit map.

The Ideal Suretrace is the market leader in this category, a basic kit seems to run about $1000.  With that kit you can follow all the wires through walls and even under slabs.



You do know you only need one GFCI per room, right?  Only the most upstream outlet should have the GFCI, the rest get stickers indicating they are also protected.