Looking for the good content out there is worth it. There is way too much of it, but there could have been more..Step-father or adoptive father scenario type for sure. Still fucked in the end considering he took care of her for years. Then again, people would've hated Silco if writers did that. If I remember correctly there is a model of him out there. Shitty TFT one though.
In general? Yes. Absolutely. Same goes for incest. Bastards have killed off so many potential games thanks to that policy.
In case of ZMSFM, not so much. He always did those hardcore noncon scenarios quite rarely. Most that can be expected from him are dubcon scenarios. Where it is technically still rape but they're into it.