Hi Jonathan,
Thank you for your help.
Yes, the parent pages are not true WordPress category pages but regular pages that will display each of their child pages; sorry for the confusion.
I will be handing over this site to a client, and would prefer not to have them manually input a featured image each time they create a child page, but rather have one of several pre-loaded images display next to the child page name and description on the parent page.
The query_post code came from a post on selecting random repeater fields I came across – I am certainly open to other methods, but am just not sure how to achieve what I’m looking for. I also plan to remove my inline CSS – was just there for quick testing purposes.
Thank you!