Android 4.1.2 build fails (API 16)

Unreal 4.15.3 problem: Won’t build to Android 4.1.2. I disabled MOST of the plugins, set my NDK and SDK versions to 16 (same as my min and max versions), set my project name and staging folder and attempted to build to Android ETC1.
It fails to build in the three attempts I made with adjustments to some of the settings, complaining about missing files and debug.apk.
Here’s the build log. Any idea what I can do to fix? I tried setting all the paths in my Project Settings and made sure the red Android config banner was green: