It depends. The Pokemon games will connect just fine, if one is EUR and one is USA. But the same isn't true for Final Fantasy 3, friend codes from other regions won't be accepted.
American DS games will work on an European DS. The original Nintendo DS handheld game console was available between 2004 and 2007.
DS consoles are not region locked, a US game will work on them just fine.
no
Yes
Yes most Nintendo DS games from the US will work on European Nintendo DS systems. However if the game is a DSI enhanced game then it will not work.
no
If you are talking about a game download, then yes, you can link them.
No there are no connection methods for the DS and Gameboy Advance SP.
Yeah they will. But you can't use a Japanese game and an American game. If it's an American D.S. and a Japanese D.S. you should use two American games, or two Japanese games. So, any kind of D.S. game can connect, as long as the games are all in the same language.
NO. It's highly impossible. There isn't even a slot in the DS for a link cable. The wireless features of the DS only works for DS games.
Yes, regular DS games are not region locked.
No it is a Nintendo DS game see related link