Thank you for the very informative page.
I would like to add the following information:
There is a Jeep taxi service that takes you from St Jacques (1689m) to Pian Di Verra Superiore (2340m). This significantly shortens the approach to the Refuge Mezzalama and Refuge d'Ayas. If you call the from the refuge on your way down, they will also pick you up again on the descent.
The Nr 7 route marker suggests that it takes 3h15m from the Jeep drop off point to the Refuge Guide d'Ayas (1h45m to Mezzalama). We are usually not the fastest group, so it took us 4h20m to the Refuge d'Ayas.