Yeah, Ghost from the movie was a wholly different character that just had the same name.
In comics, Ghost did corporate espionage (iirc, started as an Iron Man villain... although his issue was with Stark, not Iron Man). Has a sealed suit that filters his air, protects his senses, provides him with phasing and invisibility, and can directly interface with machines and computers he touches. He virtually never removes it, being somewhat paranoid.
He's a character that always seems like he should pull off more than he does... sorta like characters like Taskmaster or Batroc.
Mimic, I'd have to debate. It's easy to powergame the absolute sht out of him. Lol I don't remember the full power load-out of the Exiles, but he could permanently copy five power sets and I know they included Colossus, Wolverine, and a telepath... Jean maybe?
You know, I could always just take Purple Man. I have his write-up in one of the old handbooks. He'd certainly be different. Lol