If Uncle From Another World ever got it's own game adaption, how do you think it would play?
My guess the gameplay will be a lot like Yakuza but set in the other world.
An idea for a "summoning system" is Uncle can commune with "dimensional spirits" that when summon, temporarily take the form of Sega characters. That or they're regular elemental spirits that take temporary form to directly aid Uncle.
Can you imagine Sonic like a summoning sequence?
I think Chain Chronicles which have Uncle, Mabel, Elf, and Alicia as playable characters already nailed it.
They act and sound just like in the anime version eventhough they were released before the anime even aired.
https://www.youtube.com/watch?v=vtIIFJjoU30Of course if it was a console / PC game, your idea is more interesting.
If uncle indeed could copy his teacher's appearance, he most likely could copy game character's appearance too (they would be polygonal may be, but it's still cool).
Licensing issue is probably why the author won't go that far, but if the game was published by SEGA, almost every characters are his to mimic. All he had to do is choose.