I feel like the GX stuff, if anything, suggests a mixture of things; the fact we have an insider who seems to have basically blown the coop about Shadow while other members are teasing Isaac and Incineroar has me thinking that those could be the characters Imran, Ryce, etc. have seen (leaving Banjo, Geno, and Mach Rider as "why the f*** are you believing it" aspects).
Trying to argue that they're deliberately misleading people because they know it's real feels way too conspiracy-theory level for my tastes.
Also, the amount of characters left going on that just feels about right; while 7 seems like way too much, 2 + 1 echo (Ken) + Shadow who could be several things (either Isabelle level and only sharing a couple specials, a semi-clone, or an even further blurring of the definition of Echo Fighter) seems just meaty enough.