Thanks Guys! Yeah I see him as being "the creature from the Black Lagoon" so he was a perfect fit... Lol!
The reason why I decided to use my pre-minifigs was because I didn't want to make them the focus of my little diorama. I didn't want them to become the centre of attention - I wanted the background to tell the story, to set the mood rather than the focus to be on the mini-figs.
It's funny, White Mocha on TFW put more thought into my mini-fig selection than I did - he suggested that my faceless mini-figs could be ghosts as well - to fit in with my eerie/ghostly theme. Until he mentioned that, I'd never even thought of my mini-fig selections in that way...
Tell you what, I think I'm well & truly addicted to Bricklink - I've got 6 orders on the way...