CDG Shuttle for 10 people

You might check with G7 taxi company on their English line or on line: https://www.g7.fr/en/
and see if they can provide a reserved car with a carseat. Usually you don't book cabs at the airport but this might be an exception. There would be a 7 Euro reservation fee. The largest cabs take 7, so you are looking at two cabs with 5 each which would cost 54 to the right bank or 59 to the left bank plus the reservation fee for one cab. Just take the other cab from the regular taxi line. The prices I give include the 4 Euro for the extra passenger; standard prices cover 4 passengers and luggage.

You could also check with Shuttle inter which does provide car seats. They probably don't have a shuttle for 10 but they can be booked without pre-payment which is crucial since no show shuttles are notorious for not refunding money. You could book their larges shuttle with a car seat and the extras could grab a taxi from the official queue.

I've used Paris-Shuttle in the past: http://www.paris-shuttle.com. Also, Super Shuttle, https://www.supershuttle.com/locations/paris-bva-ory-cdg/, is in France as well, they are expensive.

We've used Shuttle Inter on several different occasions in Paris with really exceptional quality and dependability. As for traveling AROUND in Paris or getting from Paris to a train station we most recently used the Uber app and it worked out great and vastly cheaper.