Yes talk to other parents. I found that weren't at all interested but obviously in other schools that's not been the case!
I wouldn't go in all guns blazing. Give the office a ring/ email and say you have concerns about the toilet changes and want to discuss them with a member of staff involved in the project/ the head.
Get your questions down. Mine were voyeurism, children's comfort, sanitary facilities. If yours is relabeling traditional blocks then that's just a no no obv.
She addressed them well and in that particular situation it put my mind at rest. (I do get told off for that when I post it but at this primary school and with the way they did it I was reassured.
Anyway get your questions get your answers. Take it from there.