>>46660861There would be one spokesmon - I'm not cynical enough to say it would DEFINITELY be Charizard, but it very well might be - that they give you along with the Fusion Stone Bracelet. Think XY's free Lucario.
That Pokemon could fuse with like seven or eight others, including the three starter evolutions from this generation and a handful of obvious team candidates (so like, the final evolution of the early game bird, this generation's Lucario, etc.)
Then there would be a scattering of other fusions from across the cast, no individual Pokemon having more than two or three. There's a Blastoise/Gengar fusion. Alakazam/Machamp. Etc. Virtually every single fusion will contain at least one Gen 1 Pokemon; the most common pairing by far would be Gen 1/Gen 1.
There would be no daring combinations, like biped/quadruped - they would play it agonizingly safe, pretty much only pairing Pokemon with the same approximate body type. People would point at Beedrill/Blaziken as them really shaking things up, and the combination of two Pokemon with different color schemes as a based, creative design. There would be a couple of stupid wacky Galarian-Weezing-Alolan-Dugtrio-esque fusions (Hee hee hee! Electrode/Alakazam! It's like Electrode with a silly mustache!) to put on the marketing materials.
Zero thought is given to balance.