I know with the Ace Attorney games the way they keep you on track is a penalty/chances meter (I believe its 5 chances per case part) maybe that could serve as some inspiration and additional branching possibilities. Also what could help is having the suspect show stronger positive or negative reactions to the questions being asked, whether its in the art or the writing, similar to AA's extreme character personalities but to your own style that fits. Some of the reactions to the interrogation questions came off as ambiguous or like they were leading to success but fell off and I think maybe bumping the reaction impact could help players know they're on the right track.
Hope these suggestions can bring some inspiration, I really look forward to knowing more about the world you've built! ^^