Hi!
My bottom line: go straight to Nice. Read along for details.
Tickets do not allow stopovers so you would need two tickets.
The TGV does not stop at any smaller towns from Paris to Marseille. The Avignon and Aix stops do not work because they are not in their respective cities, and Marseille is definitely not a small town.
Beyond Marseille:
Toulon is not on most people's itineraries. I like it, personally, but there are no real highlights. Just a very southern-feel old town with cute shops, restored central market (now a lovely food court), and lots of questionable architecture outside of the old town. I am not sure I would recommend a stop there.
Les Arcs-Draguignan has nothing around it
Saint-Raphael is unremarkable
By the time you are in Cannes, you are almost in Nice.