The democrat's "thin RINO wall" is collapsing faster than Hillary's blue wall on election night. My guess, when all is said and done, Kavanaugh is comfortable confirmed with 54 votes. If it appears that he will be confirmed anyway, Schumer will give the red state democrats like Manchin permission to vote for him, as it changes nothing, and forcing them to vote no would just endanger their seats come November.
I agree with your analysis 100%. The only way Shumer would hold his conference together is if Republicans didn’t have enough votes. I’m sure they’ll pore over the numbers and cut free whichever red state Democrats will get a net boost with a yes vote.