I have a hacked wii on which I use usb loader to play games. Most of them work perfectly fine besides Wii Sports and Wii Fit Plus(They worked a few times afterwards when trying to launch I would get booted back to system menu)
Syscheck looks OK, there are some things I'd adjust if it were me, but nothing that would be the source of this issue.
3 things to try, update your version of gx to the version from @blackbox 's signature) or try a different loader all together just to see if it yields different results). You can also try loading the problematic games with a different cios, like 250 for example. And lastly, try re-ripping the problematic games. I think this last suggestion is the most likely to solve your issues, as the games you listed as problematic don't require any special settings, and since other games are working, it leads me to think the issue could be a bad rip.