X1800 + 2 Soundcards built in ?

Hi Im a buyer (placed order) for X1800 and just want to confirm i can use the 2 built in sound cards to record and play at same time via 2 x MacBooks I intend to use X1800 as music production mixer rather than a DJ mixer and this only Mixer on market with 2 built in sound cards

Yes you can, however, only 4 faders so you’ll have to choose per fader which USB port. Furthermore ch9-10 is master.