I live in the wrong neighborhood. I only have one cat that "wandered in" and it wasn't into my house but a former coworker's barn.
She went from skinny with a silent meow, to a big orange floof ball that will audibly meow at dinner time.
She was very affectionate from the start so not sure where she came from before that. She's chipped now though and shows no desire to go outside ever again.
Have you looked in if your local government has a catch a release program. Where I am some of the rural areas have a process where they spay or neuter, clip the ear then release them back to the area.