Okay, as for #4 [raw IP packets], I found this page at the T-Mobile forums, and it looks like it does work:
How to Get Wifi (without any data plan) to work?
[Go to "forums DOT t-mobile DOT com" and look for the "BlackBerry Curve 8900" forum.]
...open up your browser
then press menu
then select options
then select Browser Configuration
then select Internet Browser and switch to Hotspot Browser or WIFI Browser...