I'll leave this as a comment, because this isn't a full rate. First of all, mega stones can't be removed in battle, so your trick strategy with Chandelure won't work. Secondly, CB Scizor isn't viable in ubers. If you still want a Xerneas check and a steel type, I'd go for Mega Lucario. If you really want to keep Scizor, then replacing CB Scizor with Mega Scizor would at least put something Ubers viable on the team. Finally, Vaporeon isn't Ubers viable either. Normally, Primal Kyogre would be the replacement on my mind, but since you don't want to use that, running Alomomola could work. Alomomola can take on Fire types, such as Ho-Oh, for Mega Scizor/Lucario and its large HP means that it can restore most, if not all of your other pokemon's HP. Vaporeon, on the other hand, isn't able to take on those pokemon. The thing with Alomomola is that it has no offensive capability, so it really should only be used on stall teams. Keep that in mind, in case you wanted to go for a more offensive team.
Edit: Disregard the first part about Mega Rayquaza. I'm not familiar with AG rules, so I didn't realize that mega Pokemon could run items that aren't their respective mega stones. Tricking a Choice Scarf onto it still isn't the best strategy because not all sets are Dragon Dance. For example, there are sets that are just Life Orb 4 attacks or Choice Band sets that obviously don't run boosting moves. Not to mention that you're very prediction reliant because if Mega Rayquaza ends up not using a boosting move, you could end up losing Chandelure. Additionally, giving Mega Rayquaza Choice Scarf doesn't end up ruining the pokemon since it's an offensive one.
