Paul Auster's strength as a writer, and his (occasional) weakness

The third part of Paul Auster's "Invisible," labeled "fall" (first section in 1st person, 2nd in 2nd person, 3rd in 3rd person - why?) brings protagonist Adam Walker back to Paris for his junior year abroad, and there he again encounters Margot and Born, not together any longer, Margot still sexually interested in Walker, Born strangely trying again to befriend him. Hm. So where are we? Most Auster novels get increasingly puzzling and complex as they proceed, but Invisible, despite some odd narrative trappings - the central story of 1967 framed by a wider story in which a successful novelist reads th 1967 manuscript piece by piece and learns about its author's fate - is really pretty straightforward - and for that reason (to me) among the most compelling of Auster's novels. Who is this guy Born and why is he so deeply interested in Walker? How did Walkerr's life go off track after the events of '67 - if in fact it did? What's the relation between Walker and his successful classmate, the one to whom Walker sends his novel in progress? Why is incest such a huge theme of the Walker novel - did his incestuous relation with his sister, Gwyn, damage his life in some way, or is this material included for no reason? Lots of questions - leading to the final one: Can Auster bring this off? His strength as a writer is in raising these puzzlers, and his weakness can be that he can't always make good on his premises/promises. Hoping that these strands tie together in the final 100 pp.