Thanks BattlebornProductions. Your suggestion helped me figure it out!
I added the plugins included in Olivia's "Octopack Battler" project to a new empty project and tested the android deployment with Xilefian's method and Angio's fix. And it worked! So I realized it wasn't an issue with the plugins.
So I started focusing on this: "If it is stopping on a known File, would need the name and error."
The error was like 10 lines of gibberish (to a non programmer
) but you made me think that maybe the whole ten lines were one single error and caused by one specific file.
It said it was an m4a file error. So I googled that and figured out that it was a music file in the background music folder and that many other people have had problems with m4a encoding on mobile deployment.
I read those posts and I was on my way to find those files in Olivia's project to reencode them but surprise, they weren't there! There were only .ogg versions of BGM files. But there were both .ogg and .m4a of every other sound file (located in all the other sound folders: /bgs, /me and /se). So I figured it was simply an issue of missing .m4a files.
Before I encoded the .ogg files in /bgm into the missing .m4a files, I figured I'd have a look in a new blank rpgmaker project, just in case those ,m4a files were already there. And they were! So I just copied them over to Olivia's project, loaded rpg maker and deployed to android again.
Then I went to Android Studio to follow Xilefian's method with Angio's fix once again:
I edited the applicationId and changed the repositories order in their respective build.gradle file, then created the "assets" folder inside "app" and copied over the "www" folder from the rpgmaker deployment. Then I generated the APK and guess what...
It didn't work!
So I checked the app/assets/www/audio folder inside Android Studio and... would you believe it!? The /bgm subfolder with the .m4a files was missing, even though the "www" folder that I'd copied into "assets" included it!!
So I copied the /bgm folder manually into Android Studio in the correct location (app/assets/www/audio/bgm) and created the APK.
And BAM! It now works flawlessly on Android.
Bottomline 1: Angio's fix makes Xilefian's method work again.
Bottomline 2: the errors I was getting look complex to a non programmer they but were simply caused by missing .m4a files
Bottomline 3: the /bgm folder vanished when copying the www folder into assets in Android Studio, despite verifying that they were in fact present in my rpgmaker export.
I manually copied them to their correct location in the Android Studio assets folder and finally was able to generate an APK that worked!