Regarding his wife, Diana J. Mukpa, you are correct, she was 16 or so when she and Trungpa started their relationship. She talks about it in her recent book, "Dragon Thunder" which is about their relationship.
He didn't advocate heavy drinking per se - he felt that people tended to be a little more direct and honest after a few drinks. He thought it preferable to using pot/cocaine/whatever, which in the late 60s and early 70s was very prevalent amongst the "spiritual seekers" that wound up at his door. He was all about getting people to come down to earth, and felt obligated to cut through people's "trippy" fantasies about what spirituality was about, and apparently pot/coke/whatever seemed to encourage those sorts of fantasies.
He himself, however, was clearly an alcoholic and never really seemed to either hide it or to try and stop. How exactly he transitioned into a "chain drinker" I'm not sure, but towards the end of his teaching career it was clearly taking a toll on him (see e.g. Bhagavan Das's "It's Here Now, are You ?" for some stories about this; see also William Patterson's "Eating the I").
As for his sexual exploits, I believe the book "Dragon Thunder" goes into this to some degree as well. It also talks about her relationship strained her relationship with her mother, how Trungpa initially won her mother over (at least for awhile), and in general would make interesting reading for some on this forum.
I don't know if there are any on the database or not, but I have heard allegations made against Chögyam Trungpa, before his death. (At least, I think I remember him dying. It's been a long time.)
I know that he advocated heavy drinking at one time, and drank a lot himself. I met him. I never got into the philopsophy, period, but I think it was along the lines of "crazy wisdom".
He also took an extremely young (teenage) wife, if my memory serves me.