These are classic questions – they have been around for years and there are no definitive answers. I will give you my spin on these issues in a moment, but you or I, in a quick Internet search, can find several credible sources that will disagree with me and an equal number that will agree with me.
I encourage you to formulate the approach that makes sense to you and then run it by your friendly local examiner to determine if he/she concurs with your position. If your examiner agrees with your position then use that position consistently. Please understand there will other examiners that will disagree with whatever conclusion is reached by your examiner.
I know this is very frustrating, but this is the result went regulators fail to address specific questions such as these.
> One borrower dies and the other refinances – I agree with your conclusion that the loan is a refinance.
> Divorce and one party buys out the other party’s interest – I suggest that you report as a home purchase.
> Mother is dropped off the note when it is refinanced – I would not report at all.