There is no way you will get from an 0845 arrival at CDG to the CDG 2 train station for 1016 ... even if your plane arrives on time. Getting off the plane, collecting baggage, customs, and getting around in CDG is going to take more than 1:30 hours.
See Paris airport website for CDG:
Paris Airport
http://www.parisaeroport.fr/en
Gare CDG 2 (Roissy)
https://www.gares-sncf.com/fr/gare/frmlw/aeroport-charles-gaulle-2-tgv
There are several train stations in Paris with trains that depart for Irun/Hendaye with a stop at Bayonne.
If you try the SNCF website you will find there are more frequent trains from Paris Gare Montparnasse. I would suggest the train that departs at 1223 would be more achievable.
SNCF is the actual service provider; use their website.
http://www.sncf.com/
Gare Montparnasse
https://www.gares-sncf.com/fr/gare/frpmo/paris-montparnasse
There is a bus - Le Bus Direct - from CDG airport to Gare Montparnasse.
http://www.lebusdirect.com/en/
You can also take RER B train from CDG airport to St Michel Notre Dame and transfer to Metro line 4. Take the Metro to Montparnasse Bienvenue.
RATP Paris (transit for Paris)
http://www.ratp.fr/plan-interactif/
Gare Bordeaux is relatively small. The transfer involves crossing the platform from one train to the other. No sweat. The train to Bayonne waits for the Paris train if it is late.
You can do a virtual walk through Gare Bordeaux on the website. Notice the overhead signs indicating trains destinations and platforms. Your train will terminate in Irun/Hendaye; you won't find Bayonne listed.
Gare Bordeaux
https://www.gares-sncf.com/fr/gare/frboj/bordeaux-saint-jean
Yup. Last train from Bayonne to SJPdP leaves at 1806. It will wait for passengers from Paris if the train is late.
Currently the tracks for this leg are washed out so no train. Exit the station to board the bus being provided in place of the train. Same schedule and fare.
Do the virtual walk to find the SNCF bus stop.
Gare Bayonne
https://www.gares-sncf.com/fr/gare/frxby/bayonne
You might want to consider planning to stay in Bayonne for the night. The 1223 train from Montparnasse is the last that arrives before the 1806 leaves from Bayonne. Your 0845 arrival in Paris does not leave a lot of room for delays. First train to SJPdP leaves Bayonne 0745.