Okay, I love Banshee (Sean Cassidy) from the X-men, he is my favorite and I really want to see a accurate Irish version of him fighting along with the team in the Marvel Cinematic Universe, but when it comes down to introducing the X-men and who is going to be in the line up in the MCU, I think it would not be such a good idea to make him a part of the team or one of the background characters just because Fox's X-men kinda destroyed his storyline and if the MCU wants to have a shot on not messing up my character (or just killing him off!), they need to do the Hank Pym/Hope Van Dyne upgrade.

By making him an older mutant, the MCU could have lots of opportunities to get his storyline right then and there. In the comics, he loses his voice a lot and so he can't help fight alongside the x-men making him apart of the weaker members, also they could make him be friends with Charles Xavier, and so when Charles is establishing the school Sean could be apart of the staff or the X-men trainer or something.

He also has a child who later on becomes a superhero named Siryn, also the MCU wants to be more Diverse with their Superheroes, so he could be a mentor while she could be in the age group with Iceman, Kitty, and etc. Also, he dies a superhero (not by being captured), I think he should be killed off in the MCU but it should go like this, someone needs saving and he uses his full power to a super duper Sonic Scream and dies somehow. Sad but at least he saves a life.