Is it okay to make a full Shiur dough in someone else’s house and then have someone else (who didn’t make the dough and isn’t going to be baking it) make the Brachah on it? If I need to gift the dough to someone else, how is this done?

The Brachah is made by the one who is separating the Challah, even if it is not their dough and they are not baking it.