Definitely go with Wavebirds for Brawl. Classic is a no-go, for that.
As for the rest, if you're gonna want to play Resort, might as well make sure you have a Remote + Motionplus+ Nunchuk for every player. If you're just gonna get Wii Sports, forget about the Motionplus, you can always get that later then, as it's not needed for the original Wii Sports.
Nintendo Network ID: Cheebee 3DS Code: 2320 - 6113 - 9046