That is probably good enough for scaly leg mites. If you had body mites on the chicken, that can be a big clean-out. I don’t treat other birds with the vaseline or other oils unless I see lifted scales. Nustock cream for horses is also a good treatment because it contains sulfur powder which...
Yes, whenever I have seen scaly leg mites, it was only on one or two birds. Those birds usually were older ones who did not dust bathe regularly, and they did not wear down their toenails. I would treat your coop though, and permethrin dust or spray can help.
She has some raised scales that probably are scaly leg mites, but it looks like she may have injured and broken a toe. I would treat the leg mites with applying vaseline twice a week to smother the mites. The broken toe should heal on it’s own in time, but she may lose the darkened toenail.