Yes. That's hung curd. But the google confuses between curd and cheese.
Curd is fermenting milk with gut healthy bacterial culture like yogurt but in curd different kind of bacteria are used. Not by adding acid or lemon juice or vinegar. For curd we have to keep the mixture of milk and curd for a few hours to complete fermentation of the milk.
Whereas cheese is separating whey by adding acid vinegar etc from the rest of the milk - an instant process. If rennet is added it becomes cheese and if not paneer.
In cheese 96 % of milk sugar lactose is drained. In curd the sugar is converted to lactic acid.
Frankly i have not yet found answers to the rest of your questions. But since sugar is drained in whey we prefer hung curd.
May be someone can come up with answers.