I noodled on this a bit but based on your TDM threads so far, I'm going to say that in this specific instance you do not need to app Gratia separately – if there comes a point where she is consistently getting solo threads or logs of her own without Novvy anywhere in the picture then we might ask that you submit an app and use a character slot for her.

In future, I'll reserve the right to judge this sort of thing on a case by case basis and may have to make different calls depending on how people are playing it, but in this specific instance the way you're handling things is fine. That said, I do appreciate the heads up and I will probably ask in future that folks make mention of this sort of thing on their apps.