If you give away the card to your kid just leave your switch in airplane mode and you won’t have a problem. But even so it’s not allowed to do that. Btw you can also do that with a digital copy to lend it to another switch while in airplane mode.

I mean that really depends on the country, but I was talking how that usually is in my experience. In Germany you have to own the original medium of a backup and according to a quick google search same for the US.

Its legal as long as you don’t sell the original game. And as long as you don’t do that there isn’t a problem either. The issue stems from copying a game, selling the original and still use the copy. If no 2 copies of the same cartridge are online at the same time then there is no issue.

Instead of pressing the L+R buttons press the button with the 8bitdo logo while in the change grip/order menu.