Yes, more predators will be added. And no, scat will never be added. That said, the game is designed to be very mod-friendly and it has a vibrant modding community on the official Discord channel, so there might eventually be mods for that.
No, there isn't a debug console. And you can find mods in the official discord server (there's a button that links you to it in the main menu of the game).
Vehicles allow you to go to other locations faster without having to pay for a bus ride.
You improve your relationship with the characters by interacting with them and talking to them. Just don't insult them.
The facesitting scene actually has a looped animation of Jasmine smushing you with her butt. It's just that between her dark skin and her butt blotting out a lot of light, that animation could look completely black depending on your device's display settings or GPU settings.
As for your ideas and requests, I can't say or promise anything for sure.
Sorry, but no. The game being set in modern times with minimal fantasy elements is a very deliberate choice. There are plenty of other fantasy vore games if that's what you're interested in.
There's unfortunately never going to be an official version for android. However, there is an unofficial port of the game, which you can find if you click the "Eka's Thread" link and look at the first post.