Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.
Download on the App StoreAudiobus is the app that makes the rest of your setup better.
what have I done???? Restore from backup issues
Well, I went and spent a few pennies to downgrade (LTE iPad Pro 128GB sold; switch to WiFi 256GB iPad Pro; I needed the storage space)
Back up and restore went relatively well, faster than I thought it would go. However, I realized that iOS discarded the actual apps and re-downloaded the latest versions after the restore!! I thought the apps would be part of the backup, but apparently not 
I'm perturbed because I take the approach of "only update if needed" when it comes to apps and OS systems. I always read the version release notes and only update if it is critical or if there is a new feature I really want (LumaFusion greenscreen! any effect app gaining AUv3 functionality! etc)
A few notes and questions:
- some apps retained their data which I am glad for even though I forgot to make separate, manual backups. Animoog, Audiobus, MidiDesigner Pro for example restored all my custom presets, whew! high five Moog, Michael, and Dan!
- I think I lost some functionality by upgrading several apps that I was deliberately keeping on an older version. Is there any way to recover those older versions?? Is it hidden somewhere in the backup file on my mac?
- goodbye Anytune Pro. what have I done?