Elly is a pretty uncommon nickname for Danielle. Most Danielles shorten to either Danny or Elle. As I said, I thought it was very odd that Ashley never asked or said anything to MC about Elly, aside from off-handed comments where she still used "Danielle" to refer to her. Ashley follows MC's Photogram, so unless you took one of the party routes that avoids Elly entirely, Ashley should have seen that you photographed Elly. It's pretty suspicious, but I don't think Ashley's role is sinister.
I may also be missing some information. I'm only on the routes for Ashley, Elly, Natalie, and Mai, since all the other girls are way too slutty for my tastes. If any of the other girls' routes give more evidence/information, then I'd have missed it.
Yeah, she's another that seemed too slutty, so I avoided her from the start. Had no idea she was another femdom character.