Ok, no answers here so I just took a stab at it, literally.
I can confirm the stem release is similar to a 7750. In this specific case it's a recessed push button that you have to apply more pressure than you think is necessary and then the stem will slide out.
I removed the stem in manual winding mode, and the stem will go back in without too much fuss once you get it lined up however I did apply a bit of pressure to the release on re-insertion just to help it out. There is an audible "click" when it's back in properly.
As for the stab part, I have never come across a movement retention system like this before. There are four rubber slugs that sit on an inner track between the retaining ring and case. You have to slide them around with the back side of a scalpel to get them to the cutout in the movement retaining ring at 9 o'clock, then use the tip of the scalpel to stab the slugs and lift them out one by one.
Reinstallation is the opposite, just drop them into the cutout and slide them around so one is basically sitting at each lug. When all four are installed the movement is locked in place and solid.
It's a neat way of doing it once you figure it out, which took me a few minutes of eyeballing it at various angles until I knew what I was looking at.
The point of this was to reset the minute hand as it was off by a bit. Mission accomplished. Back to base Joe!