Well thought if we go for option 3, she could have normal hair until lv 7 or 8 with pigtails. And then at level 8 maybe it triggers an event like a cutscene. So that way wouldn't have to draw her hair different style for the same cutscene if that makes sense.
Sounds just fine to me, you'd have to discuss the details of the cutscene with Snacks.
As a programmer, it'd be as simple as just having the art display, so unless you're talking like actual animation, it would be very easy to add whatever you come up with