2 seniors and 2 children 10 and 11 y. arriving in CDG on a Sunday, leaving on Friday. What kind of pass is best?
If you're planning on taking the Metro or buses at least four times per day during your stay, I would recommend the Navigo pass, even though you won't be able to use it from getting from CDG to Paris on Sunday (validity of Navigo starts Monday).
There isn't any discount on Navigo passes for children nor seniors who are not residents of Paris area. Navigo is still the cheapest weekly pass.