My 4 day iterenary. Feedback please.

You would need to take the metro several times for the daypass to save money. Your child might enjoy some time in the park (carnival-type rides) after the Louvre.

Your hotel or your first metro stop can give you a map for the metro/bus/RER. Google "Paris Metro Maps" and several will come up, choose the one with the graphic you like best.

Eiffel Tower is not close to the Louvre or Notre Dame. I would put Eiffel Tower on Day 1. You can see the Champs from the Arc. You can also get a nice view of the Eiffel Tower from the Seine, but its not the same is being under it or climbing it. Depends on how important those aspects are to you.

Know what you want to see when you go to the Louvre so you can head in the right direction. You won't see everything anyway, so see what you want to see for sure.

When my kids were little, I did a couple of different things to help them enjoy art museums - either I took them to the gift shop first and let them buy some postcards of the art in the museum, then we'd go hunting for "their" art, or we'd do a scavenger hunt and see how many pieces they could find that had dogs, or hats, or whatever I came up with that day. We did do a fair bit of scrambling around, but the kids were engaged and enjoying themselves:) Maybe you could hit the gift shop at the Louvre and buy postcards of the things you want to see as well, then have you child help you hunt! Here's a website that has more ideas…http://www.gonewiththefamily.com/gone-with-the-family-adv/2012/11/visiting-the-louvre-with-kids.html.
Hope you have a wonderful trip!

Here is the website for Paris transit. Uses the "Traveling" tab for pull down menu for schedules, maps, ticket prices. Buying a "Carnet" (a pack of 10 tickets) for 13.40 euro is probably your best deal.

http://www.ratp.fr/en/ratp/r_30589/menu-annexe/

And this is the best map.
http://www.ratp.fr/en/upload/docs/application/pdf/2012-05/paris_tourisme_2012-05-29_14-51-15_281.pdf