So it turned out this kitty was a girl, again! She was much more mellow after her surgery and really didn't make a peep the whole way home or even the rest of the day. I did leave some tuna in her cage and I noticed she ate it later in the evening, which was good. I had already decided that I would release her Thursday night, which means I had kept her for about two days - same as the previous kitty. Here's a picture of her just before I released her.
She sure was excited to get back to her brothers and sisters!
One night last week when I was feeding the cats, the security guard told me that a lady who works at the school contacted a local Humane Society and they might come out to help trap and spay/neuter some cats, which would be awesome. In the meantime, I'll keep on with what I'm doing and prevent some more little kittens from running wild!