+1 on AUM. if you're doing music on iPad, it's the #1 app. It links everything together.
I'm not sure if the Arturia iPad apps have been upgraded to function as AUv3 plugins - if not, they're not gonna load in any iPad Daw.
That's where AUM comes in. It patches everything to everything, basically.
In it's core, it's a multitrack recorder, quite bare-bones. Pretty much everything you'd want to do, you do with plugins or addons. That means I have 5 different sequencers, quite a few effects, and so-on.
If you want to use more than 1 musical app at a time on iPad, you should have AUM.
I'm not affiliated with them, I just want to make the iPad music market bigger. The daws are all a bit crap, so I really want to get people into AUM. I also really like the idea of not being stuck with one developer for all your DAW needs.