France has a number of automatic snow and weather monitoring stations, notably in the Alps and Pyrenees, whose recordings are available online (as pictures, not data series AFAIK).
It seems Meteo France which runs them does not give the link to them on its public website anymore, but at least this website reproduces them daily and keeps an archive of them
After rappelling, you pull the left half of the rappel line to free the ice axes.
Before rappelling, the prusik should be positioned up near the axe so the cord is slack.
Also, the horizontal axe serves as a pulley to drive the vertical axe up (vertical) and out. So the horizontal axe needs to stay in place until the vertical axe is released.
Here are a few videos that show the technique you are asking about:
Whether one should employ such an anchor is a judgement call that will depend on the exact circumstances. At minimum, make sure to back up the anchor for the first parties to rappel and use caution when pulling. I would also want to ...
There is a video, unfortunately in German, but the steps are pretty well visible. However, be warned that this technique is not without risk:
You are only using the front part of the ice screw which increases the risk of the screw breaking out. Add an unweighted redundancy for the first people abseiling of this construction
The quickdraw could slide over ...
It's pretty simple.
Place the screw, finishing with the hanger upwards (as the rope will just be hooked over it). Back it up with any reasonable anchor, with a small amount of slack so you can tell whether it gets loaded.
Attach your retrieval cord to the screw, and wrap it anticlockwise around the screw enough times that pulling it will completely unscrew ...