Managed package gives lightning out syntax error after adding the handling of an application event

I believe the issue is access control kicking in on MYNAMESPACE:NewsFeed - there is nothing in the linkage from VF -> LO -> Lightning Out that would automatically understand that the calling VF page is in the same namespace as the component. To confirm this please change MYNAMESPACE:NewsFeed to have <aura:component access="GLOBAL"> and retest the scenario.

Unlike the previous suggested answer, access="GLOBAL" was not missing in the components but it was missing in the lightning app.

<aura:application extends="ltng:outAppUnstyled" access="GLOBAL">
    // My dependencies
</aura:application>

It took several weeks chatting with multiple tiers of Salesforce support to figure this out.