Well, all you need is the Wii mote + nunchuk you have for Zelda and Metroid. I'd buy a second Wii mote + Nunchuk for Wii Sports if you wanna box each other, and another Wii -mote for Tennis.
So that's 2 extra wii motes and 1 extra nunchuk.
No need for classic controllers, if you have a gamecube controller.