I know this is possible with other digital consoles in and around the price range of the qu16; but even after checking the manual, I am not sure if this is possible, so;
Can I stream all my inputs on the board to my macbook; and rather then record; use software like wavesrack or even my DAW (cubase) to process (EQ, dynamics, etc) and return it to the respective channel?
Not really. A channel is sourced from either the XLR/dSNAKE socket or USB. What you are suggesting is an ‘Insert Return from USB’ which is not supported. You can only insert internal FX on a channel.
However you can use plugins over USB B for send-return FX such as reverbs and delays. For example, assign a Mix to USB 19-20 in Setup / Audio / Output Patch, then route the return from your DAW to one of the Stereo channels.