I'm sorry about Vincent Van Ghoul, but I saw on info 13GOSD, there are 2 lost episodes, in total 15 episodes.
1.1 "To All the Ghouls I've Loved Before" (Pilot) Ghosts released from chest September 7, 1985
1.2 "Scoobra Kadoobra" Maldor the Malevolent September 14, 1985
1.3 "Me and My Shadow Demon" Queen Morbidia September 21, 1985
1.4 "Reflections in a Ghoulish Eye" Mirror Demon September 28, 1985
1.5 "That's Monstertainment" Zomba October 5, 1985
1.6 "Ship of Ghouls" Ghosts already in chest escape and zombie ship passengers October 12, 1985
1.7 "A Spooky Little Ghoul Like You" Nicara October 19, 1985
1.8 "When You Witch Upon a Star" Marcella October 26, 1985
1.9 "It's a Wonderful Scoob" Time Slime November 2, 1985
1.10 "Scooby in Kwackyland" Demondo November 9, 1985
1.11 "Coast to Ghost" Rankor November 16, 1985
1.12 "The Ghouliest Show on Earth" Professor Phantasmo November 23, 1985
1.13 "Horror-Scope Scoob" (Series Finale) Zimbulu December 7, 1985
1.14 "I'm Not Brew With You" (Lost Episode) Brulenda December 15, 1985
1.15 "Master of Monsterville" (Lost Episode) Katarius December 22, 1985