Welcome to the Forum, Darstan!
First of all, the sim who follows you home from a date will leave around 3 am if you don't ask to end date earlier.
Your sim won't get asked to move in by other sims in the neighborhood, so you don't have to worry about that.
If you want to move within your neighborhood, click on the phone, then real estate, then move, and follow the pop-up instructions.
If you want to keep the same sims, but have them in a different game, there are a couple of ways to do that. If you want to keep funds, skills, and job level, go to the button you use for saving the game, and select the Edit option. Select your household and choose "evict". You'll be asked if you want to save them to the library, so choose yes. They will then be available when you start a new game.
As for the voice, I don't know whether you can change that once you've started. When you first create a Sim, you can set the voice in the personality section, the tab where you pick favorites.
Hope all this helps!
