The 3DS XL is just bigger.
It can still play normal DS and 3DS games.
Yes, the 3DS XL can play Nintendo 3DS games
No, there is not.
No. 3DS games are not compatible with the DSi XL.
Yes no metter what 3DS is a 3DS
It will not work, as the DS Lite can't play Game Boy games.
3DS games cannot be played on a DS lite. You need a console from the 3DS family - 3DS, 3DS XL, 2DS, New 3DS, New 3DS XL.
There are no '3DS XL' specific games. There are only '3DS games'. The XL is simply a larger model of the 3DS, not a new device.
3DS games can only be played on the Nintendo 3DS(XL) and 2DS. Therefore, Nintendo DS and DSi cannot play 3DS games
Sometimes 3DS consoles are sold as a bundle deal with a game included, this game is a digital copy from the 3DS store. If a 3DS XL comes with a game it will clearly say so on the packaging, if there's nothing on the box then it's just a regular 3DS XL with no game preinstalled.
No there isn't.
If you download a 3DS game or DSi Ware (not DLC) from the Nintendo eShop, the game will appear on the home menu for the 3DS XL.