1. If you are new to this then I'd say keep it simple and don't get too ambitious. The save system in this game and accessing all the scenes is already a mess and what people want is more content.
If you want to go down this path then I'd say just do scene variations where it's the same sex scene but the character is swapped depending on who you corrupted more or gave more affection to and maybe come up with some alternate endings for the game based on your favorite girl or choices.
2. I'd love to see both the police and Velvet the Jewel thief as permanent characters. I think this would make a better opportunity for alternate paths as well. You either pick the police or the criminal gang and maybe offer the possibility for both later in the game
Right now my plan for this is to basically remake the game from the ground up in a different game engine from the RPGM. I currently have three other games planned to create before this one that way I have experience with the game engine and game making in general.
Most of the story will match the plot of this, but changed up a bit with how it plays out.
The ideas I currently have which is subject to change as the time gets closer.
Not going to do split paths for the characters, having to make alternate scenes for each character will be more of a pain and cause possible delays for the project.
For the character (will use bones names for this)
Martha I'm changing to be more of a stereotypical house wife focus more on doing things the old fashion way, and instead of her guilt being the reason for her corruption I'm changing it to a insecurity of not making the men in her life happy i.e. you. Still keeping her submissive nature.
Vera I will be changing how she acts. Instead of being mad and always annoyed by you being there, I am changing it to her holding a grudge against you for a choice you made as a kid, but will slowly be fine with you around. She will still be an animal lover taking care of more than just a dog and a horse, and I having her be submissive when it comes to the animals, but will be a dom when it comes to you.
Lucile I am making more into an into sports/physical activity type of person. Also having her be very competitive when it comes to any type of challenge. She will still do yoga, but won't be a fully clueless person. I will be aiming for her to be a bit on the submissive side of things. Also having her be neutral when it comes to you, not going out of her way to see you but wouldn't mind you hanging out with her.
Mia, will be you half-sister still younger then you. She will be getting the traits form Lucile such as cosplay, gaming, and dancing. Aiming to make her into a somewhat shy nerdy type who accidentally gets into lewd situations. Unlike the normal game where she has her own room, in this one she will be sharing a room with you. She will be heavily submissive in nature, following your lead.
The police officers Claire and Jules will have the two normal events of looking for a criminal. This is where I will have a split path.
If you choose to help the cops, they won't become a main stay but later Velvet will return again looking for the lost jewels leading to her becoming a main stay and you making her into a slave.
Choosing to help Velvet will lead to her not being the main stay, but the cops instead will. With them taking on the role of guards at your home. With a new thief appearing after hearing from Velvet how easy it is to trick you. The new thief will be caught by the guards and kept imprisoned by them leading to events with her and Jules.
Jules in this version will be more on the dom side, and claire being a airheaded girl and more submissive.
Remember it will be awhile before I start work on this, and the ideas listed are subject to change.