Hi Alfrede,
The past 2-3 summers have been very warm in Cham, and the glaciers have been open, with little or no freezing at night. To each his own, but I would really advise against wandering around on the glaciers alone...I know, it's Cham, and people solo stuff all the time, but people also get injured or killed all the time.
As I'm sure you know, many of the routes mentioned here do involve glacier travel. There are dangerous crevasses even on "easy" routes like the approach to the Petite Verte and the Cosmiques Arete. Again, I know, people solo these routes all the time, but there's a crevasse just below the Cosmique hut that I'm told catches many people out (or in), and the guardian of the Cosmique hut for decades apparently has never once walked to the hut unroped. I saw a solo climber fall completely into a hidden crevasse just a few meters from the heavily tracked trail that leads from the Torino hut over to the Valle Blanche.
Food for thought.
I would keep to climbs that involve no glacier travel, and limited exposure to rockfall (which has been high, because of the limited freezing).
Have fun (and stay safe).