Does the Everdrive drain the battery faster than a normal cart? Also would I need the Everdrive GB and the Everdrive GBA? Or does the latter also support GB/C roms?
The Everdrive GBA does support GB/C roms but you need to put the Goomba emulator (.GBA file) inside the sys folder on your SD card. Then it will run any GB/C roms you have using that. There is a similar option for Game Gear and Master System games.