4.) Humbert hints on page 98 that the Farlows may have had sex in his bedroom; Jean makes several somewhat sexual remarks. If there is anything abnormal in her sex life, Humbert seems to think it would be the fault of John’s indifference.
5.) This adds a certain gravity to Humbert’s assertion that he loves Lolita. However, that is neither here nor there, as by the time he gives her money and leaves (or allows her to leave), his focus is on Quilty.
6.) By which I mean he is over the hill. He has no interest in being so intensely masculine, no reason to seduce women, and his murder of Quilty (and the accompanying poem) has shown him the futility of his work. He knows himself to be more ridiculous than the people he has spent the book ridiculing.
7.) By which I mean that in the case of Lolita and Rita, he knows himself to be growing increasingly neurotic and obsessive. In the former case he is aware of his own sadism to some extent and becomes disgustingly paranoid, and in the latter though he may be helping Rita, he admits his life is hollow, worthless, and confused.
8.) I am referring to the numerous comically sudden deaths in the novel as well as the general role of coincidences and violence. He has clearly not led a stable life (picnic, lightning, world wars, north pole), and needs to compensate for the randomness of fate with his own will.
9.) I think this passage is an indirect reference to Paradise Lost, but even if it is not the parallel with Christian theology it has similar implications.