Can you use multiple audio interfaces in Ableton?
It's usually not possible to use multiple interfaces simultaneously, but you can merge them into one device by using the Asio4All driver from http://www.asio4all.com (PC) or setting up an aggregate device in the AudioMidiSetup application (MAC).
Can Ableton Live record multiple tracks at once?
You can arm multiple tracks on one scene in session view (by techniques mentioned above) and then trigger recording of them all simultaneously using scene launch. For this to work, the option "Start Recording on Scene Launch" must be enabled.