Hi, I'm experienced software engineer and I can create a script to download all properties. It would be best to load all properties into database, and once all properties are loaded, it is easy to write a query to sort or extract properties with specific last name, city, zip code, or any other field. Script will also have capability to be rerun, and therefor update the database with new properties. I have worked many times on similar projects, and if you want, I can set the script to automatically download properties several times a day, and than I can, for example, make that you receive notification once a specific item is uploaded to the website.
Lets have a chat for more details.
Best regards,
Borna