I'm tempted to agree that Ebony's the most versatile, but looking at the sheets I'd have to go with Aylia in that category. The only hole she has is a lack of magical healing; but every other ability category she at least has something. She isn't tanky at all, but even her stat deficiencies don't matter that much in Frost Giant forms. She is both a melee and ranged damage dealer. She has charisma and leadership ability. General intelligence. Flight. Stealth. Even non-magical healing equivalent to Cho's, and that's her largest gap!
In every area that I can think of, Aylia has something, whereas there's clear holes in both Cho and Ebony's skillsets; the former isn't charismatic or a leader, the latter can't fly, the former doesn't have many ranged options, the latter is squishy as hell.
Yeah, Ebony certainly has the most versatile magic--she's a traditional wizard who can have essentially unlimited spells! She just doesn't have the number needed to be as flexible, yet.
And Cho? He's a giant bug that apparently hates talking. That's nearly as much of a handicap as Dar being a cat. Better in most cases, but very much hinders social situations. Sorcery is powerful, but magic capable of anything a bug can do is still vastly more limited than "All magic", like Ebony, and mostly replicable by Aylia's ability to just be any bug, if she can copy the form beforehand.