Complex sentence: Ashly DelGrosso Costa, whose last season as a pro was season three, returned, and Edyta Śliwińska continued as the longest tenured professional on the show, having appeared on the first ten seasons.
Split into simpler sentences: Ashly DelGrosso Costa, whose last season as a pro was season three, returned. Also, Edyta Śliwińska continued as the longest tenured professional on the show, having appeared on the first ten seasons.