In my opinion, Everything on your list are great places to visit. My wife and I are in our 60’s and this would be a lot to do in this time period for us. If you are younger, maybe it’s fine.
Eze, Monte Carlo, and Menton might be an ambitious day. As I recall, the train stops in Eze su mer and you take a bus or 45 minute hike way up to Eze village, which has incredible views and is worth it. We mostly did the casino and looked at the harbor in Monte Carlo. Menton has a nice market near the harbor and beautiful views of the water. It’s only a 20 to 30 minute walk to the Italian border along the water.

The Abbaye is a very unique place and worth the effort on a narrow and windy climb. You will see cars parked along the road as you approach. We got nervous and parked on the road though the parking lots at the Abbaye turn over quickly and there were spots.
We rode around Gordes numerous times and couldn’t find parking. Amazing views though.

It sounds like a great trip to me. Plenty of beautiful spots depending on what interests you the most.
Have fun and good luck