Beautiful art, and interesting story premise.
Regarding incest: Personally, I feel a bit saturated with all the incest content and don't think it's necessary, especially if the aim is for a more believable setting (in terms of of character interactions). It would also make more sense to me storywise if it stayed as it is now, i.e. MC was taken in by Yasuka and brought the father's debt with him - if they otoh were all related to begin with Noriko has no reason to pin this situation on MC, rather she should be mad at the father (but then again she doesn't necessarily have to be rational ).
Regarding incest: Personally, I feel a bit saturated with all the incest content and don't think it's necessary, especially if the aim is for a more believable setting (in terms of of character interactions). It would also make more sense to me storywise if it stayed as it is now, i.e. MC was taken in by Yasuka and brought the father's debt with him - if they otoh were all related to begin with Noriko has no reason to pin this situation on MC, rather she should be mad at the father (but then again she doesn't necessarily have to be rational ).