plastic

Question

I know you mentioned plastic does not absorb in regard to chametz. Does it also apply for basar bhalab. Can you use a pyrex with a plastic (I think its plastic) cover as a kli rishon for both meat and dairy? or use a plastic mixing spoon in both basar and halab kli rishon pots. B)On the first day of sukkot the arba minim have stricter laws of what makes them kosher than during the rest of sukkot and it can not be used on the 1st day if borrowed or stolen. Am I correct that in a year like this, when taking the lulav on day 2 for the first time, the laws of the first day don't apply because it it not "ubayom harishon"