on laptop now.. easier to type..
How old is niece.. children under 18 are free at most sites and museums ( notable exception is the Eiffel Tower,, which is not included in any pass regardless)
Also.. where are you staying.. I find I can walk to many sites .. often only taking the metro once a day if that.. so a carnet works well for me. A carnet is simply 10 loose one way tickets, good for metro or bus.. sold at a discount to buying separately. Cost is about 14 euros for the ten tickets. The carnet can be shared .. so one or two carnets can easily do you a week.. depending on where you are staying of course.
Some sites are free.. ie.. the cathedral of Notre Dame is free..
The two day hoho buses can be fun.. I used L'Open Tour with my 13 yr old.. he loved it when we went around the traffic that circles the Arc De Triomphe.. but think that's about 36 euros for a two day pass. children under 11 are only 16 euros.
69 euros Museum pass,, note its for SIX days.. not five
14 carnet of tickets
36 hoho ticket for two days( remember if you buy this.. you will likely only buy one carnet ,, since most of your getting around for 2 days will be paid for..
11-13 boat cruise
130-132 euros.
even if you get a second carnet.. its still cheaper to buy separately.
All of those things are easy to buy there.. no preordering or paying for delivery.
A six day Paris Pass for an adult is 219 euros!!!!