Silver Bolt
Undying flames
I have no doubt in my mind that it's gen 7. Remember, gen 4 and 5 were both on the DS, so it's not completely ridiculous to have gen 6 and 7 on the 3DS. I think it's going to be more like Black and White were, meaning they'll improve on what they did with XY in a similar manner BW improved on DPPt. Or at least that's what I think. But either way, it's gen 7.