Barrett will play the supporting role of Magnus in "Kids," which tells the story of a 32-year-old man who falls in love with an older divorcee with two children and her ex's family omnipresent. Peter Traugott and Stacy Traub are exec producing the pilot, written by Hunter Covington.
Riva will play Rosie in "Lost and Found," about a woman whose 18-year-old son whom she had given up for adoption reenters her life. Marisa Coughlan wrote the pilot, with Jeff and Jackie Filgo exec producing.
ABC had previously cast Alan Tudyk in "Suburgatory," a satirical horror-comedy set in the suburbs.