NI are probably more focused on DJ stuff at the mobile app level.

Arturia have tried a few different hardware-hosts over the years, but seem to be focusing on their Astrolab platform rather than supporting iOS (Android is a non-runner due to latency).

Novation's main offerings are about analog signal paths. Back in the early 00s they had a few weird integrations like the X-Station, but its the analog nature of the bass-station and subsequent *Brute line that maintained their USP and cachet. Things like the Circuit/Launchpad are obvious AIO attempts at taking the share from similar form-factor iPad sequencing and clip launching utilities.