Audiobus: Use your music apps together.
Audiobus is the app that makes the rest of your setup better.
Band in a Box for iOS?
Is there anything close ? Session Bamd doesn’t really seem to cut it, plus it seems like abandonware . Perhaps GarageBand? I love the new BIAB , it’s tempting me to get a new laptop however it is ghastly looking . Looks like a real eye strain. I’d jump all over an iPad version though.