Your itinerary is fine for good hikers. Have you thought about last minute weather change though?

Also, bear in mind that Refuge du Col de la Vanoise (Félix Faure) might be very crowded in the summer and is certainly not a charming place if you want my opinion. It may look like a service area on the highway to Côte d'Azur at the peak of the season.

You could also alternate between huts and villages/resorts for night stops. Some are really lovely in the summer: Méribel, Le Praz in Courchevel, Champagny le Haut. Val d'Isère is fine although many cars, campervans and motorbikes transit there at that time of the year when Col de l'Iseran in open. Avoid Val Thorens, Courchevel 1850 and Tignes, which lack charm when not under the snow. Food is delicious in Gittamelon and Lacs Merlet huts.

In any case, you'd better ask for advice here: https://forum.camptocamp.org/c/rando...estre-trail/51