1: Vet theatre opening 8-down (3)
2: Changed musician not so offensively pious (13)
3: Heretic repented, holding tissue (5)
4: Simple addition in cult film (4,5)
6: Person with fixed notions is pretty sore, upset about the introduction of Ebonics (11)
7: Liquidation of one country led by pair of fools (13)
8: Don't encourage satellite pace to slacken. (11)
9: Alan, Timothy, and a couple of Estonians follow me at breakfast, lunch, and dinner (9)
10: Team directors silver cabinet? (9)
13: Model unusually creepy hat (9)
18: The color of a letter from Greece with purple edges (5)
20: Looks like an eyesore, sounds like an eyesore (3)