yup... that's what i think too... but i am careful with wording because I haven't never read the rules officiallyI seem to recall in previous years hearing about high level athletes who already would have had a bye to nationals competing at challenge, so I think it's their choice. The two young pairs teams you mentioned for sure must have byes (not only participated in the GP, but medalled), as, I expect would the likes of Lauriault/le Gac and Razgulajevs/ Lanaghan.
Will be very curious to see Pereira/Michaud (who looked very promising at their last comp) and Proft/Nadeau.