J.S.
I have never heard of a special needs photographer and I am not actually sure why that needs to be a specialty. Some photographers are good with kids others are not but it isn't like spectrum causes photography difficulties, at least none that are different than other kids. My older son was just a big a nightmare to photograph as my younger son with spectrum. Some did well, others did not.
I just feel like you are needlessly making things harder on yourself trying to find something that may not legitimately exist. Sure if you ask someone may lie and say yahhhhh I do that but they don't.
Tons of photographers do location shots, look for those.
I have to disagree to some extent with Momwithcamera, one of my favorite wedding pictures is all of us smiling, pained smiles but nice looking, big sis mumbling for little brother to chill while keeping the smile, and my son with spectrum trying to smile while screaming take the picture already!! Totally captured our family! God he wanted out of that jacket and tie more than anything on earth!