If you don't mind putting the sourcemap url in the minified JS

While I understand orgs wanting not to expose their unminified source, it's security through obscurity (meaning it's not adding any real security).

Add-ons are not allowed to contain obfuscated code, nor code that hides the purpose of the functionality involved. If external resources are used in combination with add-on code, the functionality of the code must not be obscured.

Mozilla can still block distribution of the extension, even when not distributed via ADO. It is not possible for us to provide Mozilla the unminified JavaScript source files for Google’s and Microsoft’s translation widgets. This is a risk because Mozilla can demand such.

Mozilla does not permit extensions distributed through https://addons.mozilla.org/ to load external scripts. Mozilla does allow extensions to be externally distributed, but https://addons.mozilla.org/ is how most people discover extensions. The are still concerns: Google and Microsoft do not grant permission for others to distribute their "widget" scripts. Google's and Microsoft's "widget" scripts are minified. This prevents Mozilla's reviewers from being able to easily evaluate the code that is being distributed. Mozilla can reject an extension for this. Even if an extension author self-distributes, Mozilla can request the source code for the extension and halt its distribution for the same reason.