I had
https://www.amazon.com/Mayflash-Nin...sr=1-3-catcorr&keywords=mayflash+gamecube+wii
and it worked in smash bros wii and wii u as if it were a classic controller.
I however didn't like it as the gamecube cable would keep coming out during play. It came out really easy, maybe mine was defective, who knows. I have since lost it so I can't test it in nintendont.
However keep this in mind:
Hypothetically those adapters should work, but will act like a classic controller or classic controller pro. Which means the L and R buttons might get treated as digital instead of analog (Remember, I have not tried it and it may depend on who programmed the adapter), making games like mario sunshine difficult to play.
FYI: The Classic controller works fine for sunshine, The Hori Gamecube gamepad and classic controller pro do not. But for playing like mario kart double dash, all of these controllers work fine.
The official Gamecube to USB adapter from nintendo works great for me on my wii u.
I would test my adapter for you but it is lost... sorry.
Also if the games you want to play don't use the analog LR buttons, then it should surely work.
edit,
I have had no issues running gamecube games from SD cards. They may load slower than HDD, but it is still probably faster than the laser the gamecube disc drive, So you are probably alright as long as it's like a class 6 card or higher.