The problem is, the thing that people loved about The Manor was the artwork. And the story. Both of which fulfill all criteria to be covered by copyright.Why? I do not need to nor want to, feel free knock yourself out on some light reading on the past few pages maybe you will find out why suing will not work out the way you think it does, page 1146 is the end of that talk i guess you can start there. If you are talking about the characters, outside of the artwork there really not much to copy this is really, is just a standard incest story that barely started.
Take these away and, sure enough, it's just another cookie cutter incest game. But take these away and you'll find zero supporters willing to pay for your project.
Just want to bring it out here: Remaking the game and keeping it faithful to the original will get you patrons and legal trouble. Removing the offending bits won't get you in trouble, but won't get you patrons, either.