I agree fully with your 3/ and 4/. I also agree with your 2/, simply adding that what this was his rational reflection; his feelings had already integrated her disinterestedness.
I dont agree with your 1/. He had already a true love for Elizabeth, not a mere infatuation. I could not tell exactly when this true love started, but I do think it was already there (and HE believed then it was a mere infatuation, or maybe even a mere attraction) at Netherfield when he told her his faults so openly, he had already lowered his defenses to her - by his defenses, I don't mean the way to matrimony, but that of a total confidence he doesn't have, for instance, with Miss Bingley whom he has known so long...
I should precise that "true love" for me, and I suppose for Jane Austen as she was Church of England, is St Paul's agapê described in chapter 13 of his First Epistle to the Corinthians, and read at every marriage (I send a link to Wikipedia). And Jane Austen gives so many trials to this love, as to make us understand its true nature.
It is true that Mr Darcy has not yet aknowledged how unexceptional Elizabeth is, and how worthy of being loved - he has aknowledged it only partly.
And above all, he is not reconciled with himself. He believes he is acting wrongly, asking her in marriage. And he is so much engrossed by his own "struggle", his own (supposed) guilt, that he forgets her own feelings! - her feelings which, one must say, he cannot really guess because he does not know her as well as he will, after her refusal. And he has enough vanity, to believe he necessarily pleases any girl; or at least, not to imagine he could please not any girl (he is not so far from truth there, as at first, before his slighting at the assembly, it seems that he did please her)...
Of course, in his mind, he cannot conceal these struggles. He is perfectly right and honest when he tells her : "disguise of every sort is my abhorrence", but he has not taken a great care of "respecting" (in your acceptation) her and trying to soothe the expression of these struggles.
This is why, in spite of the excuse of being "out of himself" (English culture rejects it as an excuse but Jane Austen seems to see there a symptom of strong love), one can say that his love is not pure, not mature, not well-tried, not improved.
But it is still love.
A mere infatuation would not have born the blow of such a strong refusal. Without love, he would not have wanted to hear anymore about her. Instead of that, after a night of reflection (cannot we guess that he did not sleep a lot?) he rises to write her a letter, once again open-hearted and even more confident than all that he had done before. Not only has he wholly forgiven her, he maintains his love to her (not his proposal, which were "disgusting" to her; nor his "wishes", as she has refused him), a love without seeking any return.
So, I must assert that he is truly loving, of a deep love, but a love needing improvement, and his feeling guilty of marrying her too is wrong, it is a love-killer, better than any sonnet... ;-)