Ellie Vaughn's Links
Ellie has very complicated feelings towards Cas. They're both on good terms, but she never really knows what to say when they talk. Ellie still deeply cares about Cas. In truth, there's still some romantic attachment lingering in Ellie's mind, but they know better than to try and act on those feelings again. She wants Cas to be happy, and she knows that she isn't "the one" for him.
Cas still has great feelings for Ellie, being as that she was his first real girlfriend, but the feelings now are purely platonic. She appreciates that Ellie stuck around as a friend, and that they didn't immediately abandon them when Cas saw their relationship would go nowhere. Cas also appreciates their friendship together doesn't make the entire friend group awkward. In conclusion, she still absolutely loves Ellie, just not romantically anymore.