Watch some of his more recent action movies, it might help. He hasnt lost much from his roots as a boxer.
I just don't see Adam Baldwin as either one. He strikes me as too young for Morgan, whom i see as older, more weathered, and more angular around the face to compliment the beard. For Michael I think he could work on pure physical build, but I have serious doubts on his ability to portray the humble righteousness of Michael, or the quiet kindness. Not saying he can't, but I haven't seen him in any role even close.
Yeah, I was trying to stay away from picking actors and actresses based on both their physical characteristics and acting chops, as that would be a heck of a lot harder to cast all 36 folks from my limited knowledge of the acting folks I'm familar with.
I think the last thing I saw Neeson in was Phantom Menace, so I can't say anything about his more recent movies (besides being the voice of Aslan in the Chronicles of Narnia movies).
I'll give you the point about Morgan.
From the physical standpoint, it was kinda frustrating for me to figure out these two--I know of several actors who I thought would have made a great Michael or Morgan at earlier points in their career, but are now either too old, not old enough, or have packed on a few too many pounds.
How about
Tom Selleck for Michael or Morgan? He's more weathered and older, although given the choice, I'd cast him as Michael instead (barring Neeson)