imy Hometown is Paris, i dont know before you can print the Ticket for the Eifeltower, very good information..
about the transportation, from the airport to my home, or for you the hotel, no question only the taxi.
i dont will take the metro for free, alltime full, then 2 person, each have 1 big bag, again for free i dont take the metro.
the bus from Airfrance is ok, when the stop is near, very near the hotel. if no take a taxi.
It sounds like you are arriving at 6 PM and leaving early the next morning with Children.
if that is the case, you have really got a task on your hand to make this a very enjoyable experience.
You may want to consider this:
Stay at The Marriott, CDG, contact their Concierge (Can be done via The Hotline, or call them), explain your situation, and see if they can arrange to pick you up at CDG.
Upon arrival, go directly to hotel, get checked in and then follow their advice on the quickest way to go directly to The Eiffel Tower.
See The Eiffel Tower, then take taxi to C-E, find a place you would enjoy dining and have dinner.
Take a taxi back to C-E and prepare for your early morning flight.
The key to making this easy may be how much support (from the hotel you choose) you get from The Concierge. They don't mind being contacted and have really helped me in the past.
Let us know how we can help, and the best of luck!