What is max. ethernet speed? 100 Mbit or 1 Gb? First one should work with TX6 image. Not sure how wifi could work (it's not enabled on TX6) unless it's based on USB, but that would be very unusual. Detailed photos of both PCB sides would also help.
For your second question - there is no way to install pyhon2. Kodi announced that this would happen a couple of years back, but a lot of addons are still not updated. If you have addon source, you can try to rebuild it with python3 dependency, but very likely it won't work well without changes.