I do wonder how JJ will get on with coming into a production that he does not have full control over. Lucas is clearly going to be attending meetings and speaking up about what he thinks should happen because it is very much his baby and he is protective of it. In addition to this many positions of producer & writers etc have already been taken up by people appointed by disney and lucasfilm.
JJ is used to having full control over his Star Trek movies and can write & mould them into exactly what his vision is from the ground up. I dont think he will get this freedom on Star Wars.