Help with ile de France metro plan

I would just go ahead and buy the two weekly passes. No you won't use them all seven days, but you will be using them enough in each separate week to make it worth the money (and the saved time vs. buying individual tickets).

Adding to the above: you would just need to purchase a single ticket for CDG to Versailles on the Sunday (I think it is a bit cheaper than a "Navigo jour" day ticket).

Guerino I to have my previous Navigo Decouverte that I plan on recharging when I arrive in November for the first week. I may just get the new Navigo Easy, https://parisbytrain.com/navigo-easy/, for the two full days & departure morning to CDG the following week. It sort of replaced the Carnet (book of 10 tickets) back in 2019 & no picture needed to set up the card. I just need to sit down and figure out the cost difference & what I will be doing

Last I read the Easy will only accept an airport trip, and a carnet of ordinary metro tickets -- so it would not work for Versailles but would be fine for your excess day and airport trip and it is not time limited. Use the ND for the full week. You would need either a taxi or an RER ticket to get to Versailles and again on Monday from Versailles to Paris Opera you would need an RER ticket -- the Easy would not accommodate either trip unless they have changed to allow it to load RER fares.

The Navigo Easy card accepts tickets for the Roissybus/Orlybus, tickets t+, or Navigo Jour (day passes). The only option which might work for you would be a Navigo Jour fare which could also be loaded onto the Navigo Découverte card you already have.