Eh, my quick takes:
-TPC can't force Sakurai to include a Pokemon if he doesn't want to. That makes no sense at all. If Sakurai hypothetically wanted to cut Incineroar, it's up to him, not them.
-Working in the games industry,
papagenos
theory isn't outrageous or impossible.
-Incineroar makes sense as bait if you think of bait from a different angle. Instead of being used to track leakers, it's used to keep a real leak from gaining traction. If every leaker bands together dismissing the real leaks cuz no Incineroar, it keeps it surprising to the public when those leaks are true.
Personal conclusion: it's a 50-50 toss up for me if banner is real. I lean towards real, but not strongly. If real, I give Incineroar a 1% chance. It doesn't make any sense for the banner to be incomplete when likely the printed materials won't be public until after full roster reveal. If fake, I give Incineroar a 90% chance.