I never transferred anything Wii to the Wii U. I figured my Wii system works fine so no need to put extra wear on the Wii U with Wii functions.
Not that I know of. 8bitdo has some great Bluetooth controllers. The SNES ones look/feel exactly like the first party ones, just wireless. Granted, buying a bunch of new controllers is more costly than buying one or two adapters for controllers you already have. I just mean if you’re angling for something with an authentic, old school feel, you have options.
Yeah, the idea here is that I don't want to buy more controllers when I already have some that work perfectly fine. Sure they may not be as convenient as wireless controllers but I grew up with cords so I can tolerate them. One of the reasons I bought the SNES Classic was because the controllers also work on Wii U and Wii, so if I could also use them on Switch then it would be some nice added value for something I probably didn't really need.
I haven't tried it myself but I believe you can use GameCube controllers via the Smash Bros. adapter when your Switch is docked,
Oh yeah, I forgot about that port being an option. I've used the GameCube controllers for a few Switch games and aside from missing a few buttons they work just fine.
The only adapter I've managed to find for Wii plugs (the same type the SNES Classic controllers use) is one that plugs into a GameCube port, so on Switch that would mean the controller is going through two adapters. I'm not sure what that might mean for latency. Also, the adapter costs about $30 which is a little more than I was hoping for with an adapter.
Do you have some Wii U Pro controllers? Buy the bluetooth adapters and get more life out of those! Considering I paid $100 for both those Wii U Pro controllers it is nice to get more value out of them.
8bitdo and
mayflash have ones for ~$20. I use the Mayflash one and it works just fine, also nice knowing that it is usable with Xbox and Playstation controllers in case a friend wants to use one of those.