The ZED series mixers (Mini, 2-Bus, 4-Bus & ZEDi-8*) are capable of recording two channels of audio to your DAW simultaneously.
You can change the USB record bus assignment to AUX or Master L-R but the two-channel recording restriction still applies, it's an either / or scenario.
*LR Pre or LR post options available. There is no Aux mix on the ZEDi-8.
The ZEDi-10 and ZEDi-10FX mixers are capable of recording four channels of audio to your DAW simultaneously.
You can change the USB mode between:
M1, M2, M3, M4 (four mono input channels assigned to the USB sends)
M1, M2, Aux, FX (first two mono inputs and the Aux and FX sends)
M1, M2, L, R (first two mono input and the LR or Main Mix post)