Yes, there are considerable (~1 km) stretches where the path is exceptionally stony, due to a non-switchback/non-water-management trail construction practice inherited from the Romans, in which the pathway becomes a streambed in the rain, and an eroded dry wash in the sun.
A few, quite memorable.
Several, equally memorable
It can be, depending on how many Canadians, Swiss, Germans, and Dutch pilgrims are traveling your week. MMD lists English-speaking lodgings, and making reservations there in advance is a help - they fill up fast.
There's an adequate supply of information available. You may need to learn a few words of French; but you'll need to do that anyway.
Not necessarily; the Germans will habitually walk 30-40 km days. But you are traversing the South of France, eating home-cooked French meals guilt-free. Why rush through it?
At 58 on the Le Puy in September, you'll count as a spring chicken.