The analyses of a text #3

The narrator recalls his adolescence.
He visited his old friend Traddles' place for the first time, and there met his old friend Mr. Micawber as Traddles' land lord who had been a debtor quite a while.
And he invited Taddles and the Micawbers to his apartment.

....................
Mr. Micawber then delivered a warm eulogy on Traddles. He said Traddles's was a character, to the steady virtues of which he (Mr. Micawber) could lay no claim, but which, he thanked Heaven, he could admire. He feelingly alluded to the young lady, unknown, whom Traddles had honoured with his affection, and who had reciprocated that affection by honouring and blessing Traddles with her affection. Mr. Micawber pledged her. So did I. Traddles thanked us both, by saying, with a simplicity and honesty I had sense enough to be quite charmed with, 'I am very much obliged to you indeed. And I do assure you, she's the dearest girl! -'
Mr. Micawber took an early opportunity, after that, of hinting, with the utmost delicacy and ceremony, at the state of MY affections. Nothing but the serious assurance of his friend Copperfield to the contrary, he observed, could deprive him of the impression that his friend Copperfield loved and was beloved. After feeling very hot and uncomfortable for some time, and after a good deal of blushing, stammering, and denying, I said, having my glass in my hand, 'Well! I would give them D.!' which so excited and gratified Mr. Micawber, that he ran with a glass of punch into my bedroom, in order that Mrs. Micawber might drink D., who drank it with enthusiasm, crying from within, in a shrill voice, 'Hear, hear! My dear Mr. Copperfield, I am delighted. Hear!' and tapping at the wall, by way of applause.
[David Copperfield by Charles Dickens]
1. I'd like to know what "them" refers to.
2. I'd like to know why it is "drink D," not "drink to D."
3. And I'd like to know what "here" means here.
Thank you in advance for your help.