In the original: Armstrong is a sort of comic relief character. Very strong and proud of his body and lineage, he works with Mustang to try to undo the crimes of their past and tries to protect the Elrics.
In ours: He's the wise sage type, still comedic and still protective, he always has words of wisdom that everyone tends to agree with. Except, his voice is always muddled because his mustache is so thick. When you audition for him try to make it sound like he's chewing on his mustache through his lines. Almost like Kenny from South Park.