For Wii:
So with your 2 Wiimotes you can play 2 player games that support that controller.
These are games like New super mario bros, wii sports, Mario Kart (look at the back cover's of games and they say the controller types at the top right).
Games you wont be able to play will be ones like Zelda Skywards Sword because it requires a nunchuck.
Some games are easier with a nunchuck or a classic controller (
https://upload.wikimedia.org/wikipedia/commons/9/9d/Wii-Classic-Controller-White.jpg) like mario kart.
WiiU remote plus works the same as normal wiimote but I believe there is some issues using those controllers during the softmod process?? Don't take my word on that but just remember something about that?
For GC:
You will be able to play 3 player with what you have.
2x Ps4 (via usb cable) and 1x WiiU pro controller.
You will be able to play 4 player once you get a few classic controllers or nunchucks.