Checking for any mineral deficiencies is good, even very minor ones can inhibit sleep. Ours was more the calcium and magnesium but I've heard iron can be an issue too. SPD kids get so overstimulated, it's hard to calm down and sleep well, is she getting enough breaks/calm time during the day? Conversely, is she getting enough exercise? My DD sensory seeks at night too, she needs soft squishy stuff like this huge stuffed dog, weighted blanket, soft down comforter, ect. Most nights she does sleep in a bed in our room too, she has a lot of separation anxiety, to me it just doesn't make sense if she's too anxious to play in a room by herself she's not going to sleep in a room by herself either. A lot of these milestones seem to happen slower for our kids, they do seem to happen eventually though.