I'm really hoping they can maaybe hack in wireless multiplayer for Kirby and the Amazing Mirror, but Ice Climbers is a good start.
Sadly, unless Nintendo changes its plans, they won't.
The NES games were the only ones they said would be receiving updates, and even then it was only when they released to the general public. Nintendo was clear from the start that they had no plans to release the GBA games to the general public, nor did they ever give any indication of plans for future upgrades to any non-NES VC game.
Besides, unlike NES, GBA is a handheld, and multiplayer linking between handhelds work very differently than consoles which simply support multiple controllers on the same system. Since multiplayer hasn't been supported for any of the GB games, it's a pretty reasonable conclusion that GBA won't be any different.
The only games we can safely expect to support multiplayer at this point are Ice Climber, Balloon Fight, and Yoshi.