1. There are no "design rights" but there is a copyright on the plans. There doesn't seem to be any interest in enforcing that copyright, however, as PDF copies are abundantly available. Good luck getting the templates in full size, though. Most scan/print operations introduce significant distortion.
2. Your biggest challenge will be finding and fitting a suitable engine while maintaining CG. And fitting good brakes.
3. You're not missing out on anything from the Q-Performance list.
