Do not get the switch light. That is only hand held. The OLED version has a better screen, so if you think the kids will want to play it in handheld mode you could get that.
But the standard switch will work just fine. And honestly your kids probably wouldn’t notice a difference.
I would reccomend getting a couple pro controllers or another set of joycons. You’ll want to have at least four player options for Mario kart and smash bros.
Also those are the games to get.
The new mario game looks fun. Super Mario wonder.
I love zelda. You could get the Breath of the Wild game. It’s older than the new one. But it is great. And on sale sometimes.