I haven't had this problem exactly, but I'm wondering if something we had with DD might be similar....

My DD also had reflux and probably came off her medication around 7ish months. Everything was going fine....at around 10/11 months she started vomiting (as you described, emptying the entire stomach) every time we gave her yoghurt and then smaller vomits after other dairy (e.g. after her cereal with cows milk). I wondered if it was something to do with the dairy side of thing (although she had been having yoghurt and cows milk on her cereal for quite some time and never had any previous issues). I stopped giving any to her (besides cheese) for a few weeks and then slowly introduced it again and everything seemed fine...... Do you think the sudden switch to having so much cows milk might have something to do with it???

As for how we weaned to cows milk....we haven't completely yet. DD has two bottles a day (both formula) and has cups of cows milk with meals during the day.