Hehe letsgoflyers81, he said "no 'I thinks'"
1. No, wmodem is not ICS. Wmodem is the old tethering app (has existed in more or less that same form for 4+ years) whereby the PPC becomes (for all intents and purposes) a modem on the connected PC and the data connection is created and initiated on the PC side (which by nature disables the connection on the PPC itself). ICS/Internet Sharing debuted with later builds of WM5 and WM6 is most peoples' first occasion to use it. Rather than a modem-based setup, Internet Sharing uses IP NAT to actually share the PPC's internet connection with the PC, so both devices are connected to the internet simultaneously. The PPC hands the PC an IP address and directs traffic from the PC just as a home router (or PC setup to do ICS) would.
2. Internet Sharing is incompatible with bluetooth DUN, because they use two different paradigms to accomplish tethering.
3. Yes, you can have multiple PAN connections to a WM device... however due to the processor speed of the PPC doing the NAT coupled with the modest speeds of the EV-DO network my hunch is you would not really get very good performance out of such a setup.
4. Again, Internet Sharing is an IP NAT application, so no modem stuff there. That's where wmodem comes in.
5. Unhiding them in the reg unhides them for wmodem.exe, not Internet Sharing. Internet Sharing is via USB (NDIS) or BT PAN only. Actually there's a recently-published hack to do it over wifi as well but still--no modem-based anything. Wmodem is what you're after--it is capable of USB (serial) or BT DUN and simulates a modem on the connected PC. However, I have not checked to see if the BT DUN profile is included with the mogul. If it isn't then that probably explains why the DUN reg entry keeps getting set back to 0 automatically.
The multiNAI reg entry, BTW, is useless... always has been. Useless for wmodem and doubly useless for Internet Sharing.
If I can answer any more questions let me know.