Interesting map. I had no idea that CPS went so far West past Woodland Golf Course.Essentially. In the attached image, I was able to get CAGIS to show the school districts boundaries (yellow for OH and light red for CPS). There's also a gray line kinda in the middle that goes by Glencrossing Way, Anderson Ferry Rd, Muddy Creek, etc. that I believe is the boundary between Green Township and the city. You can see the locations of St. Antoninus, OLL, Covedale School and a few other places for reference.
I think the idea of the houses being built before Oak Hills existed as a school district makes sense. I have a relative that lives on Earlwood, just off of Antoninus, and their house was built in 56 I do believe. Oak Hills didn't become a district until 1959, when the high school opened.
Here is an article that shows the timeline of how/when Oak Hills consolidated..... focuses primarily on schools in Delhi, but it's a timeline nevertheless.