Hi,
We got our dog when he was 9 months old. He had previously been no problem during the night at his previous home (the breeders) but of course he had other doggy friends to keep him company. We were absolutely certain that he would sleep downstairs at night, after all how hard could it be!!!!!
When he came to live with us he was understandably a bit dewildered and didn't like being separated from us at night and would howl non stop. I slept downstairs with him to begin with and of course he was fine. When I tried to distance myself from him at night he began the howling again.
Our daughter was only 2 1/2 at the time and we too were worried about waking her (although she never did) so we made the decision to let him sleep upstairs. This resulted in a good night sleep for everyone. Ironically as time has passed and his confidence has grown he now spends at least half the time sleeping downstairs.
I'm sorry this doesn't add anything new to the thread and there are a lot of COL's who have tonnes more experience and knowledge that me. I don't have a magic cure, and it sounds like you have tried a lot harder than I did. But imo if its a case of everyone getting a good night's sleep v's being at your wits end with stress then sleeping upstairs wins eveytime.
Good Luck