Decided to create a topic to localize things pertaining to containers and lists. Two attached files. One focuses on lists only, the other works with both lists and normal containers. The "list" file includes exporting to Excel, while the other just debug prints the results.
References:
https://blogs.msdn.microsoft.com/visio/2010/01/12/custom-containers-lists-and-callouts-in-visio-2010/
https://docs.microsoft.com/en-us/office/vba/api/visio.page.getcontainers
https://docs.microsoft.com/en-us/office/vba/api/Visio.ContainerProperties.GetMemberShapes
This link has additional code related links:
http://visguy.com/vgforum/index.php?topic=8686.0
Wapperdude.