For sure, if the guy has one of the 7 Ushpizin names, you should absolutely be dating him on the day of his Ushpizin.
e.g. If the Guy is called Moshe, date him this Friday; or if Yosef, date him this Thursday; or if Yaakov, date him this Wednesday.
Needless to say, on Chanukah, if the guy has the name of a Shevet or a Nossi or the father of a Nossi, absolutely date him on the day of his Nossi’s Korbon.
It is pathetic that someone would see the prospect of “dating” (as we call, the term means something different in American English) as so mournful as to be inappropriate for a time of simcha. Perhaps the person who asked the question believes that “dating” is only appropriate for Tisha B’Av?
Most black hats fulfill the minimum requirements for a sukkah, so if the girl thinks the guy might not be frum enough to wear a black hat on the date, she should bring one to the date to provide him with the opportunity to fulfill this mitzvah. The guy should bring cookies baked by his mother so that he can make a leishev, but she should MAKE the leishev because you obviously wouldn’t trust the bracha of a guy without a black hat. And he should wear heels for pirsumei nisah.