You cannot transfer data between the 3DS and Wii as they are not the same console. You can only transfer data from the Wii to the Wii U or the Nintendo DSi (XL) to the 3DS and to 3DS XL.
The 3DS does not have a slot-2, it cannot use any accessories developed for it such as the Guitar Hero addon or the DS lite rumble pack. Those are only compatible with the original DS and DS lite.
If your 3DS is updated then go to system settings, click other settings, then scroll through the pages until you see the "system transfer" button then chose Nintendo 3DS to Nintendo 3DS. However that doesn't copy it. Also extra data is deleted for that game. Also you will need to download it again.
go to the settings in your 3DS, in there go to other settings, then go right twice, there you can see system transfer, go in there. do the same on the 3DS XL and then follow the instructions.
Save data is tied to the 3DS that wrote it, so it should be clarified what you're trying to do. If you want to plainly copy the data from one 3DS to another 3DS, this is not possible. The other 3DS will be unable to use this data as it was not written by that console. If however you mean you want to do a System Transfer and retain the game's save data on the new system, you perform the transfer first and then swap SD cards over, and the new console will treat it the same as the old one did.
No, Pokemon data is still stored on the game card itself, not on the internal memory of the 3DS.
No, the 3DS cannot obtain downloadable software including Virtual Consoles and Save data from the Wii.
All 3DS applications and games downloaded from the Nintendo eShop can be deleted from the Data Management section of system settings: From the Data Management menu, select Nintendo 3DS, then software. Select the application you want to remove, select "Delete" and confirm.
First click on 'data management' then 'system settings'
The 3DS memory card is for downloaded games and their save game data. It contains your streetpass data, and you can add music to it too. Photographs and videos you take using the 3DS can be copied to the SD card also.
To erase games on your 3ds you go to: 1)System Settings 2)Data Management 3)Select what genre it is (3DS Ware or DSi Ware) 4)Click on it and touch #Delete#
All 3DS applications and games downloaded from the Nintendo eShop can be deleted from the Data Management section of system settings: From the Data Management menu, select Nintendo 3DS, then software. Select the application you want to remove, select "Delete" and confirm.