Honestly didn't know there was such a system to classify NTR. I am personally a fan of Type A, in this case. Maaaaybe Type B as long as its tied to corruption. Not a fan of NTR works where the girl doesn't *willingly* start enjoying it by the end.
Where A is willingly and C is completely unwillingly, B is a middle ground where the the heroine starts unwilling but starts enjoying it at some point. B is usually a common favorite as it has most impact in some sense and the whole process of corruption is given a lot of delicious attention. Feels more satisfying when there is an initial barrier to overcome. While B can include any method of corruption, I feel mind altering substances or mind control are not as good as good old blackmail combined with seduction.
This game is doing NTR A in a very solid way, actually made me realized how few good works of type A I have seen in the past. As you are planning of adding more heroines I was almost expecting for some more type B leanings to mix things up, but if your plans were type A heavy I think our little valet might stay as the most reluctant girl around, which might not count due to her relationship status.
In any case, I really look forward to the new content teased, Natsuki is looking great, she has that perfectly balanced body compared to the two previous heroines. I am kinda worried what her and her husband's kink is and hope it allows some of the same delicious secrecy as with Mary. Hanako has that gloomy hairstyle that makes me wish we get to see her eyes in good moments, maybe even see her change her hairstyle.