Do you have the Ravenloft book? The loup garou from that book is a CR 13 werewolf that would be a good start for a werewolf formI think the "ever-evolving" Strahd is a good idea. I'll bring in the animated armor to join the fight. And the sunlight from the holy symbol and Sunsword will only be effective in his vampire form. When he turns into a second form (I'm thinking a big werewolf) it won't affect him. The rogue has a silvered short sword, so she'll get a chance to shine in that portion. I'll need to keep an eye on all the character's HP and spells - and then just adjust to make sure I'm not completely overpowering them.