Umm.. is no one going to talk about how he know she cut her hair!? I thought he was blind!

Elios actually explained that he can see but not the way normal humans do (which is with their eyes)

did you actually read this? there is a chapter where he explains how he "sees" things almost like geolocation... and throughout he's been able to figure out all sorts of things about ppl's physiques... not just the hair