iPad / DAW integration

I’m looking to put together a hybrid set-up, to multitrack hardware gear + iPad into Ableton. The iPad is the sticking point at the moment… Ideally I’d want a digital connection rather than headphones out + Ableton Link.

What are my options and what are you using for this? The popular choice seems to be the iconnect audio 4+, but I’m going to need way more ins (+/-16), and this one doesn’t seem to be expandable (unless I’m missing something). Also my understanding is that running two interfaces simultaneously on Windows is a problem(?)

Any ideas / suggestions / thoughts appreciated!