ʿAwjāʾ is a feminine descriptor whose basic sense involves curvature; here it evokes the energetic bodily motion of a swift she-camel. It does not describe an infirm or defective mount.
Mirqāl describes a camel given to irqāl, a rapid, extended gait. Tarūḥu concerns travel in the evening, while taghtadī concerns setting out early. Their pairing indicates not merely two clock times, but a mount capable of sustained travel.