Games that a that your kids can play together (5 & 7) online?
Basically only minecraft on that list is suited for that (imo).
Like mentioned above (by wyrdness) Mario Kart is another option.
That said not sure how easy to use online + play together is on the switch, esp for kids.
Might be easier to just play games split screen, local multiplayer, and hand them each a controller.
Necro-bump this 2020: http://gamrconnect.vgchartz.com/thread.php?id=229249
Bumb in 2021: http://gamrconnect.vgchartz.com/post.php?id=9047071