Hello,
I am one of the developers from the old forum that is also seeking to make the WAVE 300 work.
I have made a new thread to track the issue, perhaps you may find it interesting.
As far as the GPL issue goes, as was written on the old thread, it is probably in the best interest of the community to first make the driver work, and then try to resolve the licensing issue possibly by contacting Intel.
Intel has generally been a great supporter of OSS and OpenWRT, and it is likely also in the best interest of Intel to have mainline support for this chip. I believe the decision to change the license to proprietary was made by Metalink or Lantiq before being purchased by Intel.
Anyway I wouldn't worry too much about the GPL issues if the driver doesn't work in the first place, so I believe that's the first step.
Good luck,
Vittorio