CPDLC is for taxi clearances, etc. It is not intended for tactical situations like crossing runways, takeoff and landing clearances, etc. So CPDLC would not have helped.
Since the controller knew he had similar sounding call-signs, why tell both aircraft to lineup and wait on intersecting runways. Simply, placing SWA on the runway and clearing them for takeoff and then you could immediately clear DAL for takeoff. The time to taxi onto the runway and start takeoff roll would never have casued a problem.