[oZo]

Okay, I performed a hard reset, not a clear storage.
I installed the cab you have linked to, nothing else.
I installed PHM regedit and did the edits exactly as you listed.
Still I only have <none> in the dropdown menu.
The only difference I see is that you have written:

[HKEY_LOCAL_MACHINE\Comm\InternetSharing]
MaxCMCon=0

My phone has:

[HKEY_LOCAL_MACHINE\Comm\InternetSharing]
MaxCMConnectRetries=0

Everything else is exactly as you recorded.

I even tried entering Sprint in 2 different ways.

[HKEY_LOCAL_MACHINE\Comm\InternetSharing\settings]
ForceCellConnection="Sprint"

and:

[HKEY_LOCAL_MACHINE\Comm\InternetSharing\settings]
ForceCellConnection=Sprint


This is a real puzzler to me.
Thanks for your time.