Thank you for your quick and helpful reply!
I think I understand what you're saying. So it might be easier for me to determine Change/Steadfast first and then approach Start/Stop a little differently depending on whether the character changes or doesn't.
So a Change character who needs to Start is often someone who is characterized by a lack of involvement/bravery/initiative-taking (like the MC in Casablanca). He needs to take action rather than going with the flow and watching things happening around him.
Meanwhile, one who needs to Stop is TOO nosy/active/risk-taking (like Hamlet). He needs to stop doubting, testing, worrying, or basing everything on past experiences, and to trust and let things happen.
So, because Steadfast characters don't actually need to change, they mostly just need to be steadfast in differing situations?
So... a Steadfast Stop character just needs to stay steadfast until the bad things stop (like Shrek)?
And a Steadfast Start character needs to stay steadfast until good things start (like Eliza in My Fair Lady)?
I'm still a little fuzzy on the Steadfast-ers. Do I seem to be on the right track?