Outta Bass supports Interapp Audio (IAA) connections as a Generator. (MIDI can be sent to Outta Bass via virtual MIDI)
It is best to launch Outta Bass from the IAA host app as it gives Outta Bass the opportunity to configure itself for IAA prior to starting any engines.
Audiobus connections to an existing Outta Bass instance are possible but you need to switch to Outta Bass after connecting as its needs to complete is configuration while in the foreground. Reconnecting to a previously connected and ejected instance is not recommended. Quit Outta Bass after ejecting it.