Thank you for your post. If your labels are embedded in a geospatial PDF, they will show up based on how your map was made. If you would like us to take a closer look at your map and provide you with suggestions, you can share it with us via help.avenzamaps.com.
However, as you mentioned, bringing in a KML file of your data and having all placemark labels display at once would be ideal. This is a feature our developers are looking into, and if it gets implemented you will be informed.
If you have any other questions or problems, please don’t hesitate to let us know, or contact our
Support team directly through help.avenzamaps.com
Avenza Systems Inc.