[Ronin]

Echo didn't hold the mantle for very long at all - she passed it off to Clint pretty much as soon as she came back and joined the team. Like, so fast that an Echo-as-Ronin card doesn't really make sense. (Especially with the context that it wasn't supposed to be her in the first place, yeah)

Clint had a longer stint with the Avengers as Ronin, held the mantle through Dark Reign.

I've thought about the Ronin-as-a-mystery angle a few times over the years, but honestly I think it's hard to do in a compelling way. Makes more sense to just focus in on Clint I think.