Medallion Status Change and Upgrade

[pilot]

I have some questions and after some searching I found some older answers and want to know if they are still the correct answers.
I dropped to GM last year after years of being a PM. I'll be PM again after Monday's outbound flight. While I'm in a Y fare and already upgraded, I'd like to get in on the PM time frame for next week's flights as they are M fares. So here are my questions:

1. Does Delta still do the Saturday status upgrade sweep or is it more real time now?

2. Do I still have to call and have them remove and re-add my SM number to my PNRs to reflect my new status?

3. If I am already upgraded, what will removing and re-adding my SM number do to already upgraded flights? Nothing, lose the upgrade, anything?

4 (and last question) With free Crownroom club and priority checked bags (not that I ever noticed them being priority) now gone, is there any benefits to PM besides higher upgrade priority, PMUs and reduced/no fees for award travel, doesn't look like it but I thought I'd ask and be enlightened?

TIA
-swps