Right, the new evidence after PD can not be used for RFE. Try to get 2-3 recommendation letters from Europe to emphasize your international recgonition. Draft a very good response letter for RFE. I had DIYed my RFE and got approved in one week. Good luck!
It really depend on what your RFE points out. In my opinion and experience in dealing with RFE, I would say, the new papers can be used to strengthen your authorship, but it will not help on your contribution parts. Meanwhile, meeting invitation will not help either. Sometime, (not all the time, the USCIS clearly states the they only accept evidence before your submission date, and only on the parts about contribution and review. Therefore, in short, if you want to use for criteria authorship , it will not have problems, not other parts . Most of time, the RLs are not qualified if IO did not buy it.