Just thought I would follow up now that we are back. We decided to go ahead and purchase both the Paris Visite (transit) pass and the Museum Pass through the Airport website (see original post for website). The website worked OK. The confirmation emails were a little confusing - the information is there, but the layout is very odd. Finding the Tourist Information desk in Terminal 2E was a little bit of a challange. We were tired after the long flight and weren't sure if we were looking for something before baggage/customs or after. It turns out it is nearly at the exit - so definitely after baggage pickup and customs. Once we found the desk, there was a line. There were 2 people working there, but it definitely moved slowly. However, once we finally got up to the desk, they had everything ready for us and it only took a few minutes. (It would be helpful if they had a special line for just "order pickup" but I don't have any hopes of that ever happening in Paris.)
We also ordered a TravelWiFi (small device that connected to the cellular network and provided a WiFi access point for our devices - travel-wifi.com) It was also available to pickup at the same desk. That also was a very smooth transaction. We waited in line for 15-20 minutes, but picking up both passes and the TravelWiFi took only a couple of minutes.
One note: If you decide to do this and you are being picked up by a car service, you might want to let them know. We decided to go ahead with this only a few days before we left and it never occurred to me to let the car service (EZY Shuttle) know. Our driver was clearly unhappy about having to wait. Since we actually got our luggage and through customs/passport control really fast, I'm not feeling too terribly bad about it, but it would have been better if I had let them know in advance.
Another note: The Paris Visite pass made using the RER and the Metro very, very easy. I'm pretty sure that individual tickets would have been cheaper, but we avoided waiting in lines at ticket windows, trying to figure out the machines, etc. It was nice to just hop on the metro and get all over Paris without having to stop and figure out if we had enough tickets. We went to DLP our 1st day and I would have hated having to figure out how to buy the RER A tickets that morning. With the Visite pass we were able to just go straight to the train with no problems or confusion. The pass is currently a tiny (same size as the t+ regular tickets) cardboard thing which we treated very carefully so we wouldn't lose any of them. However, we heard that they are going to be switching to a plastic card more like the London Oyster card, so that will be much better.