No. Like the normal-sized DSi, the DSi XL has no GBA slot.
Only in the original Nintendo DS and the Nintendo DS Lite. DSi, DSi XL and 3DS do not have a slot to put GBA games into.
Pokemon Emerald was only released as a GBA cartridge, the DSi XL has no GBA slot so you can't play it.
No, the XL does not have a slot-2, which is the GBA slot on a regular DS or a lite.
The original DS can play them, as can the DS lite. The DSi, DSi XL and the 3DS do not have a GBA slot.
No, only GBA ones. You cannot play regular Gameboy or Gameboy Color games on a DS.
Yes, the Nintendo DSi XL can play all Nintendo DS games, except for Guitar Hero, which requires a slot-2 add-on device. The DSi and the XL do not have a slot-2.
No because the Nintendo DSi XL does not have a GameBoy slot.
There is a bottom slot to the Nintendo DS where you can insert your gameboy advanced game. However if you own a Nintendo DSi or Nintendo DSi XL, then you cannot play gameboy advanced games.
No, the DSi XL does not have a slot-2 for GBA games.
Considering the huge size of the new DSi LL/XL, which does not have a GBA slot, it is unlikely a further model will have it. It was initially removed from the original DSi due to size constraints, the console would be just too big and bulky for what Nintendo envisioned for it.
It is compatible with all DS games apart from any that require Slot 2, which the DSi and the XL do not have. (There is no such thing as a DSi XL specific game.)
Unfortunately no, Guitar Hero: On Tour and it's sequels cannot be played on the Nintendo DSi, Nintendo DSi XL, Nintendo 3DS or Nintendo 3DS XL. All these systems do not have Slot-2 hardware (Game Boy Advance slot), which is the main requirement for this title.