The plural form of sheep is sheep. So "Sheep give" is correct. It's the same as "They give".
No definitely not, only cow milk and soy milk are common here, sometimes you can find drinkable yogurt like in China but for the most part Vietnam is like Americas California
Especially after all the tourists came in the 90's to destroy the country
It is used mostly for Greek and Italian type cheeses. Cheese not real big in Vietnam as far as I could tell. One restaurant gave us snacks before dinner an included the individually wrapped gooey kind of cheese that we spread on bread.