Jr. didn't answer certain questions at those meetings because Republicans in Congress didn't push for those answers. But now, thanks to Cohen, we have different versions of events that Jr. either lied about, or didn't give an answer to. He'll plead the Fifth, because there is no chance he can answer questions honestly with different stories. He already got caught lying about the adoption story, as did Trump. He will have to plead the Fifth. He has no other choice.