If you can run an extension cord outside to a makeshift bench for all heating procedures, I would recommend doing so... the fumes for both plastic and lead will ultimately precipitate somewhere and you don't want these to mingle with any surfaces that might touch your food. (Andy's recommendation for a dedicated microwave should be strongly considered!)
Non-airborne particles are much easier to monitor/contain, so assembling lures, tying, and some painting can be done safely inside with some "good housekeeping" practices.