Thanks to a color printer and some card sleeves, I've actually tested these. The most recent version is up in place of the previous image file.
Igor: At the moment, I'm considering changing Igor a little. I like him as he is now, but it takes too long to set up a Frankenstein's Monster. It's not that hard to do, but it often happens after the Curse pile is empty, and in any case, he just feels late to the party in general.
I'm considering making Igor cost 5 and changing from +2 cards to +1 card. I think the handsize-neutral optional trasher is cool and all and should probably cost 7, but it just isn't helping the Corpse Token mechanic. Thematically, I even like how Igor is this totally obedient servant who hardly ever does anything against your wishes. I'll probably test it sometime.
Vampire: Kind of fun, but he can really steal the show in combination with some of these other cards. He totally trivializes the Werewolf buy-in penalty. Poor Mummy, only gets used as Zombie fodder, if at all, on Vampire boards.
Werewolf: Would be OP without the Silver bane. With the Silver bane, this card is just swingy as hell. A lot of Dominion cards are, but whatever.
Ghost: Originally, this card cost 4 and did not return itself to the supply. When you trash Zombies with Vampire to gain Ghosts and VP all day, though, you rack up a lot of Ghost and the cantrip mini-Torturer attack is kind of a bit much. When it costs 2 and returns itself to the supply, it makes it feel ephemeral, *and* makes buying it for the trash effect (moneylender, used-up curser, etc) a fair trade with a little one-time bonus thrown in.
Zombie: This card is really tricky. I can't ever figure out the right game tempo for this card. Sometimes you can ignore the Zombies and power through VP, and other times, a three-pile ending with Zombies, a 2-cost action, and another 2 pile is dominant. Sometimes you just want to tuck a Zombie away here and there for the +1 VP, but then you need a careful balance between disposable actions, Zombies, and your real big players; treasures + zombies + junk actions + trashing might be decent on some boards, but it's really, really tricky.
Zombies were inspired by Rats, but I made a few changes to fit Zombie lore a little better (they only "infect" actions, they prioritize "eating" Actions, they decay if they don't have things to trash, killing them gets you VP.)
Sexy Scout: Harem/Scout mashup. A really stupid card that I'm a lot more likely to buy than regular Scout, at the very least. They're terminal and anti-synergize with themselves, so they don't spam well. Can be a nice pickup on the shuffle where you start to green hard.
Bat: 3 cost for a weak cantrip attack! Sounds fair! But it sucked. It just stopped you from buying enough Silver, and even with a bunch of them, they usually don't Wishing Well themselves that often. At a cost of 2, it's a solid card to soak up your spare buys, and you really can build an engine of them if you really want to try it that badly. In this case, Vampire-Bats could actually kind of work, maybe...