We flew into CDG last year and will be doing the same this. Neither of us are very good on coaches, so we caught the TGV.
In theory the TGV is a good idea, but as the journey was to be only 10 mins, we stood with a 4 year old and luggage. Unfortunately this was near to the loo. We had to keep moving cases and a very unhappy child so that people could get to the loo. Then the train was late leaving and people stood outside getting a last minute fag. We were gassed........
This year we will be hiring a car from CDG and driving to Disney.
With the luggage, last year we left it at left luggage at the train station. It is on the 2nd floor and has big lockers. I am told that you can also leave it at left luggage in Disney, but have never tried that.
Hopefully someone will give you more info on the coach transfer, but you would still be able to leave your luggage at the train station. Depending on your hotel, it may be possible to leave it there.
Em