Casting Actors for "Rose-Tinted" Film

Mikey is a quiet, emotionally heavy person who feels everything a little too deeply. Whoever plays him needs to handle subtle vulnerability but also flip into raw, impulsive emotion when things boil over. Great for an actor who can say a lot without talking much. What I'm looking for are expressions and actions.

Robby is the loyal best friend who tries to stay strong even when he's hurting too. The actor needs to balance laid-back friendliness with moments of real emotional honesty, especially towards mikey. I'm looking for someone that can play someone that can make the audience feel sympathy for him but can also express anger.