What I called the Edit Songs page is what you got to by clicking Repertoire >Setlist > Solo > Edit Songs.
I looked at your data on the server and I can see that you do have a Split View layout sized for your iPhone 7 Plus in landscape orientation, so I don't know why you're not seeing it. If you submit a help ticket, then I can look at the data on your device and see if it's there:
https://helpdesk.arlomedia.com/arlomedia/add.htmlAlternatively, you can click Settings > Account Sync > Reset Local Data and see if that brings it back.
Or tell me which existing layout you'd most want to use, and I'll add the automation button to it for you.