"Always Sunny" star Glenn Howerton also joins cast of small-screen adaptation
Hanks joins a cast that includes Billy Bob Thornton and Martin Freeman
Coen Brothers adaptation will also star Billy Bob Thornton
All characters in the new series will be original, FX says
"30 Rock" vet takes his talents to colder climes
"My Generation" writer will pen adaptation of 1996 crime drama "Fargo"
Cable net's highest-rated scripted series will air pair of crossover stories in August