Mofu man, at this point, you just need to ignore this. The ideas that's the fans have offered to you are nothing more than that, just ideas. In the end, the development had to be done by you alone, you are the sole developer and artist, so you should feel proud of your work. You shouldn't feel like you need to actively destroy 3 years of development over this nonsense. These messages of harassment will only bring your project to its destruction, I guarantee it. So at this point, I would ignore it all and simply replace the characters you don't feel like using so at least you know the new ones are yours. And keep moving forward with your vision, don't let this pressure get to you. There are more fans who aren't crazy that want to support you. These users harassing you have no power over you, you dont even have to respond to them. Be strong.