I think you misunderstood some parts of the guide, let me help you.
In your w7 Gisette convo, you don't need a good relationship with her to convince her to peace. The choices during the Gisette relationship check are "Yes, I do" and "Best not", choosing the latter will let you avoid the check. Now, before that choice, if you have 30 or more rivalry with her you will get +1 WRONG (or +2 if 40 rivalry, or +3 if 60 rivalry), but if you haven't pissed her off much beforehand it should be fine.
(For the record, saying your goal is Katiya's legacy gives +10 rivalry, not having all aquit for trial and just most aquit gives +20 rivalry. Katiya's Legacy pretty much requires all aquit so you probably should redo it if that's your goal.)
And yes, Zarad will help you before the trial if you're romancing him or have 25 friendship with him. Tell me if you need help on befriending him.