Catherine,
I am with the others re time between Ste Chapelle and ND Eternelle. For me, Ste Chapelle would be best, but for the 13 year old, do the Eternelle. Try to book another time for Ste Chapelle. Maybe early on Thursday? Or switch the Eternelle to Thursday and work around that., but definitely take the teen to the Eternelle. I am thinking you could allocate about 3-4 hours total to Montmartre/Sacre Coeur, but that is me. You would then have a half-day for Ste. Chappelle or Eternelle, whichever you can change, and depending on reservation time, maybe fit in the catacombs. (I've never been to the Paris ones, but have been in Rome. I understand they are different from each other.) If not enough time, skip the catacombs.
Comments about going through the lines at Ste. Chappelle are right on point.
The rest of your schedule sounds good. Although I love Rodin, choose the army museum. There's lots of armor there, even for horses, and overall should be more interesting for the teen.
With time you could do both after the ET summit., especially if you forgo the 6:00 p.m. Ste Chapelle visit. We have often done a kind of loop...ET (from below), then Musee de l'Armee, then Rodin...all walkable from one to the other in the order I mentioned. I don't know how long your visit to the top will take. It's been way too many years since I ascended. Of course, you will have to find time for dinner somewhere that day.
Your teen will have a wonderful experience in Paris. We took our kids when they were 8 and 10, and 18 and 20, and they each went on their own after college. They still (in their mid-forties) cherish their visits there! Your teen will too!