They are just lights, so there is no reason they couldn't be re-wired to work. It would be like wiring up auxiliary lighting - run power to them through a relay and find a signal wire off the headlamp switch that will trigger the relay - not sure how they will work without a driver module though). I have no idea if any modification would pass whatever inspection you need them to pass - you would need to determine that.
PIU headlamps do not have signature lighting. I'm not sure what headlamps you bought, but if they are retail headlamps with signature lighting, I'm not sure if those can be made to work on the PIU or if the headlights will work, just not the signature lighting part. Maybe jmr or someone else can confirm.
Best of luck.