For minigames, I would recommend using the classic tic-tac-toe asset… just to give it some good Roblox nostalgia. I would also throw in things like spleef, people seem to enjoy that.
Map ideas, I would say Low poly would work best. It’s easiest on most younger audience’s eyes. Younger children like more basic structures as they can understand what it is just by looking towards it and not having to process all the details.
Personally, I think Low poly is always better for games with a purpose that aren’t based around realism. It’s also better for performance.