Teloch asked: If the Firefoursome found out about his date with Jin.
It depends on what their relationship is like. If the girls are the jealous type, and only accept that Zuko has other girlfriends because they're also dating said girlfriends, they'll be, at least, very irritated, and if Zuko is ever on the same city as her again, they're likely to throw a fit.
If they a have "the more, the marrier" mentality, they're gonna ask Zuzu to take them on a vacation to Ba Sing Se so they can meet his "friend."