Busdriver01,
How would you get the legal ability to live/work in the USA ? That's the critical factor; everything else is just details. I haven't heard of a visa arrangement (like the Aussie E3) that would help you as a Brit but I'm not a subject matter expert by any measure.
Your brief statement of qualifications would seem to indicate you're OK for regionals and maybe even an LCC (heck, maybe even a legacy). Getting an FAA license is an expensive process...unless you can get a regional to pay for it.
The current hiring/upgrade frenzy will certainly come to a halt for any number of reasons so don't count on it as a permanent situation...but that's another subject.
Since contacting airline HR people is so easy these days, I'd email every single one of the regionals and LCCs (contact Spirit for sure) to explain your situation. See what they say or suggest. Or if you're a glutton for punishment, fill out apps to all of them...and email their HR people.
In any event, good luck and let us know what you discover.