1. Moreover, is there a way to download the enhanced voice packages from within an application? (e.g. a package dependency, or a system method to invoke the download)

I'm seeing this issue in the release version. When opening the app, or clicking on "Check Installed Fonts..." from the menu, the message dialog pops up for me. I've uninstalled and reinstalled the latest version of SF Symbols and developer fonts. Are there ways to see the details, etc.?