Sorry for missing the modem type in the subject. You seem to be doing the right things, but left out this from the first posting here:
That is an issue yet to be automated. Maybe the modem info extracted by usb_modeswitch can be used to determine which modems need the USB2.6. Tips for some special situations:
a. To override the default number for ttyUSB0, change the number in /etc/modemttyUSBnum; some modems use ttyUSB2.
You are correct in not using any of the old patches. (I need to update the first posting to take out all references to them.) If you have needed the special versions of the option and usb_storage drivers (also on the first post) before, you will continue to need them with 4.1.2 or 4.2.1.
The PIN issue depends on your situation. If you have disabled it in Windows, you should not use the PIN in Puppy. Otherwise I would think you need it. But now, it will be sent only on the first connection attempt. So, if it fails, simply disconnect and reconnect in pupdial.