Please share thoughts on my Paris itinerary

Chez Hebe would give you a very nice meal.

Here are my thoughts:

Arrival day: This will work fine since it's a Sunday? You do not need to book ahead for the Pantheon or Cluny Museum so you can cut that if you don't feel like being inside. Or go earlier if the weather is not good, lol. Any interest in Roman Paris? I did myself a DIY Roman walk in the Latin Quarter mostly a few years ago and would be happy to share the high points if that is of interest to you.

Day 1: I would actually move Day 3 to here as I believe Palais Garnier is open Mondays. You can do all your other things this day too.

Day 2: This is fine. I would not bother with timed entry tickets to Notre Dame unless you all want to climb the towers. If you just want to visit the Nave the entry line moves fast.

Day 3: This would be a Wednesday? I would do the Orsay in the AM and Hotel de la Marine in the afternoon with lunch in between. If you've got the energy you can head to the ET area. Are you interested in Art Nouveau architecture? There are some awesome examples of facades by Jules Lavirotte near the Eiffel Tower.

Day 4: This looks fine. I'd have some indoor back up ideas in case it's rainy. There is a nice museum in Montmartre or you can drop back down to the Marais and go to the Carnavalet Museum which is free and is the museum of the history of Paris.

Enjoy your time in Paris!

Beach teacher,
Flipping day 1 and day 3 is good advice. And I would Uber or metro to the Arc de Triomphe. It is uphill and a ways from the Opera Garnier and Galeries Lafayette and will take up a lot of your time and energy. I confess I am not enamored with the Champs Elysees and find it too commercialized. Looking down at it from the Arc would satisfy me.
Day 2 looks fine. If you can fit in some time to stroll along the river on the left bank, say, from the Pont de l'Archeveche, you will get the classic (for a good reason!) view of Notre Dame. Then take the Pont au Double to the front of Notre Dame, do your visit, and then a short walk to Ste. Chapelle. (Just a suggestion). You still have a good amount of time to wander the Marais unless you are really late risers. And you can see Ste. Chapelle first if you wish. I just wanted to stick in that stroll along the left bank, if it works for you.
If you flip days 1 and 3, you could go to the Musee d'Orsay instead of the Hotel de la Marine on day 3. (It would be my preference, but it is up to you.) The whole rest of the day (late morn to cruise time) can be spent in the Eiffel Tower area. (What I do, since I don't ascend the Tower any more, is admire it from the Trocadero and/or the Champs de Mars.) From there you can walk to the Invalides (Army Museum) and Napoleon's Tomb, then to the Rodin Museum and Gardens (a particular favorite of mine. I have been 6 or 7 times.). Or do a reverse. Walk to the Rodin after the Musee d'Orsay and have a light lunch in the cafe there (good food and inexpensive), spend an hour in the gardens (oh! the sculptures!), walk to Napoleon's Tomb, then see the Eiffel Tower, I envision an early entry to the Orsay, then arriving at the Rodin around noon, 2 hours there including time for lunch, a walk to N's tomb and visit there (90 minutes total, if interested), and getting to the tower by around 4. There are river cruises that leave from the Eiffel Tower area, so you can make a 5 p.m. boat ride easily. (Of course, if you ascend the Tower, my times won't work out quite the same.)
You day 4 sounds good. Remember, there is so much in Paris, that if you change your mind on something, there will be a dozen other things that pop up to substitute. And, of course, a wander and a cafe stop will always be memorable.
Amusez-vous bien!

Beach teacher,
You are very wise to have made your dinner reservations. be sure to double check them closer to the days. (I am a suspenders and belt person.)

Arrival Day - pump the brakes! The Pantheon AND Musée Cluny is a lot to see on your first day when you're still jet lagged and just arrived in Paris for the first time. I'd stick to strolling around the Latin Quarter and Jardin du Luxembourg and having a nice dinner. Just wander around a bit and get your bearings, get a feel for the city, get some fresh air. Save the museums for another day.

I love the Cluny but it may not be a great idea on arrival day. My husband took a great picture of me and our two young adult kids sitting on a bench there nearly falling asleep when we went there on our arrival day some years back :- )

StellaB and Patricia make a good point about arrival day and not trying to do too much. Play it by ear. That being said, I do hope you find time during your visit to Paris to visit the Cluny. It took me 7 trips to Paris to get there and I loved it! It is now high on my list of Paris favorites.

Thanks everyone for the great suggestions…this is just what I needed! Great idea to switch Day 1 and Day 3…that way we can see Musee D’Orsay. I think Hotel de la Marine looks beautiful but if we can only fit one in this trip, I think D’Orsay would be our top pick. And for arrival day I guess I’m trying to be optimistic that we get a great night sleep on the flight over, in main cabin Lol! Even if we don’t get to it on arrival day, I’ll try to find at least an hour or so to see Musee Cluny. I think it’s very close to our hotel and I’d really like to see it.