Just read the last ten pages and am horrified at your situation, Changenamer.
Whilst I can see that you are doing what you think is best for your DD and DSD, and while they are small (how old is DSD?) it may actually be the case, please believe me, as a child of a similar marriage (with one hell of a lot more intermittent shouting, which took place after we had gone to bed but we heard it all, nonetheless), it won't last.
As soon as your DD is old enough to have a mind of her own, she will start asking questions, maybe answering back - how is your H going to react to that? If he's anything like my father was, it will be badly. Such men are lovely fathers while their daughters are compliant and well behaved. Any sign of anything else gets treated very harshly.
She will notice the drinking. We all did, once we were old enough. Although she didn't mean to (I hope), as the eldest my mother used me as her emotional crutch and then would rewrite history, whitewash things, lie to my face to keep up her facade of a happy, loving family. She couldn't even admit it to us while we were all living with it and now denies it ever happened and tells us we 'exaggerate'. Or the subject will be changed. The consequence of growing up being told that what you witness/feel/hear isn't true is that I can't trust people. Not even my lovely DH, not completely. It has scarred me.
One thing I saw in your original post really worried me - that you 'big up' your H to your DSD even though you don't mean it - do you really think she won't suss this out and start to despise you for it? Does her mother do the same (big him up)? Because if not, the conflicting messages are not going to be doing her any good at all and will lead her to distrust you.
When my mother gets maudlin for my (now-deceased) father and goes on about what a great provider and a generous man he was, I shrivel inside and it makes me dislike her intensely because she cannot admit her marriage was anything other than a success, even now he's gone. I suppose the lies become a habit and then become your own version of the truth if you keep them up long enough :( . Much as I love my mum, I have no respect for her because of this. Is that how you want your DD/DSD to view you?