As far as I know admission fee is valid for all the visitors. Bur there are some reduced rates for certain people. Better if you visit webpage. Best Regards. Fatih Bulu

Non saprei

Yes, you do need to line up again . The best thing to do to grab lunch inside the museum. They have a good assortment of sandwiches and baked goods. And don't forget to buy your souvenirs inside the museum if you want European made goods instead of Chinese junk.

There is no dress code. Since it will be July, it will be hot, so wear light clothing. If you plan to go into churches while you are walking around Paris you might need to cover your shoulders (a light scarf in your in your bag will do the trick). I listened to a lot of Americans that live in Paris on TikTok for advice and one thing they said was to wear covered shoes even in the summer. The reason is that like any big city the streets are very dusty. I found this to be quite true. If you wear comfy sandals make sure they are they kind you can wash!!

The Arc de Triomphe is in the middle of a round about but there’s an underpass to get to it safely. No ticket required for this. The Louve is in a huge square which is really beautiful to wander around, sit and relax also no need for a ticket. Enjoy your visit.

La cosa la troverai lo stesso quindi ti conviene arrivare sempre 30 minuti prima perché nonostante l’orario si forma in coda lunga lo stesso

Acho que é possível revender na hora. Não tive essa necessidade.