NES Virtual Consoles support multiplayer, but not GBC or GBA. However, as of the end of this month, it's expected that people will reverse-engineer the Pokemon VC containers and allow all GBC VC games to link.
GBA will probably never have it though.
If anything, grab a couple of flashcards and a couple of GBAs and you'll basically have 100% compatibility barring specialised games (Such as the e-Reader and games using the solar or tilt sensors).Yeah i figured that it would happen with the gbc. Just kinda hoping for some gba multiplayer for nice trips back to childhood with my fiancé haha