Paris itinerary help please (short time period in Paris)

I have used an organization called "Paris Walks". They have organized walks with specific topics. They seem to take a large number of people per tour. They also do tours in museums. https://www.paris-walks.com/

Another option that I think might be awesome for you is Paris Greeters. I have no experience with this group, I've just read bits about this program in Paris and in other cities. It's free and they can base a walking tour just around you. The person doing the tour wants absolutely nothing. It is my understanding that people that use the service might donate to the organization for overhead costs. Maybe they could provide two greeters. One to be with the children for more child centered things (as a mom, I'd still want an adult in that group, as I think a greeter would as well) and then another greeter to handle another small group for more adult activities. Or maybe one group takes a tour with a more traditional tour organization and then the children along with an adult stroll the city looking for kid friendly fun?https://greeters.paris/en/

If weather is nice, you could pick up picnic supplies and eat in Luxembourg Gardens, or pick up some sandwiches or falafel in the Marais and eat in Place de vosges. It's a beautiful park with a sandbox and you can see where Victor Hugo lived (tho I think the interior is closed for renovation.

Regarding the Monet water lilies- are you sure you want to go to the d'Orsay, and not the Orangerie? The former only has one if these paintings,IIRC, while the latter has the rooms full of the large paintings. And the Orangerie is just a stroll thru the Tuilleries to the Louvre. Both museums have cafes or you could do an al fresco lunch in the park.

Cjean, is correct and I think that the Orangerie is an especially fun experience for children. How often do you see paintings that big! My kids always enjoyed a book called, "Linea in Monet's Garden". If you don't have a copy you might want to pick one up. I think it will get the children really interested. Linea visits Paris with an adult friend and stays on the Ile de St. louis and visits sites with Monet works. Another thought I had with the Louvre for kids is to take them to the gift shop before the tour and preselect some post cards of things you know are in the museum (not in storage or on loan) and that you will see and have them select one to be on the "look out" for.

You have said that you will be arriving from Avignon at Gare du Nord.

I expect that you know that you will actually be arriving at Gare de Lyon, and it is then an RER or Métro or bus ride over the town to Gare du Nord?

Yes, thank you- you are correct. We arrive at Gare du LYON from Avignon.

Thanks you for the help on the itinerary. I was apparently confused about the water lilies paintings. I am so thankful for your help!!