In reply to tehmarks:
Question 1)
It is usually best to get live information by talking to the wonderful friendly staff at the OHM. This website is very useful with regular updates:
https://www.chamoniarde.com/en/mountain-topics/mountain-conditions#HdwbkA2n...
Many guides give conditions reports, here is one example:
https://www.alpine-guides.com/climb/planning-your-climbing-trip/alpine-clim...
Question 2)
Not sure how to answer this as AD is not usually a snow plod. A great easy and accessible short AD route that may fit the bill is the Grisolle on the Tacul. Depending on conditions and skill of party a mix of moving together with perhaps eight pitches of snow / ice / mixed. To the right the Mazeaud is similar but harder.
Shorter and easier, the Table Couloir is great as an introduction, usually need to be early in the season to catch it still in condition. In the same area, the traditional snow plods and scrambles of the Tour, Tete Blanche and Petite Fourche give a couple of days fun from the same hut ( Albert Premier ). You can also extend the day and add harder sections such as the Tete Blanche N. Face ( good snow conditions required ) and linking the two Tour summits.
The area around the Torino hut has lots of short routes to have a go at and link. Entreve, Tour Ronde, Toule, Flambeau, Marbrees.
The challenge with all the snow routes is to ensure they are in good condition. Appropriate overnight freezing levels, good snow cover, perhaps rocks projecting for more protection opportunities. Usually best to have several areas / routes in mind and then pick the one in best conditions.
Question 3)
I don't have up to date knowledge of the Pissoir but I do know that conditions vary hugely each year and the tendency is for it to be out of condition earlier and earlier in the season. I believe there is a lot of snow around at the moment, but this can change very fast.
Have fun!