I am not a beach fan-girl either, I understand where you are coming from!
Picture #1 – You’re right you do not need to mess with the natural beauty of the house, it is beautiful on it’s own and doesn’t need much but a few accents of simplisitic sexiness. Why not try adding pool decorations that float? http://offbeatbride.com/2012/06/pool-decor You can also think about putting candles all around the pool or leading out to the where you can have a lounge for guests like so:
A few ottomans, few lines of fabric from Joanne’s Fabrics or drapes from Target, couple of candles or string lights and you’ve set an amazing atmosphere for your guests. You could even have the ottomans in leather to give that “rocker” vibe, along with dramatically colorful candles in all shapes and sizes.
Picture #2 – I see palm trees and other little shubberries there, why not add flares of red light in the bushes, or lights around the palm trees?
Picture #3 – I would personally fabric up that cieling like this: http://www.weddingdecoratorblog.com/2010/05/decorating-the-ceiling-with-fabric/
As for the last picture it is the kitchen and I don’t really see why you should change it. Maybe switch out some of the light bulbs with different colors? That could be fun.
For the colour scheme if you want to play around in the Halloween area, you can play with yellows, creamy oranges, different shades of black (yes it is possible), with soft touches of green and/or red.
If you decide to pull away from the Halloween theme you can get color inspiration from the house itself, but instead of like a pool blue, go for a dark, rich blue. If you choose a yellow go for a deep, sunset yellow, and deep pinks, purples and playful blush reds.
Staying within the Halloween theme invest in black lights.
There is a website called the offbeatbride.com (http://offbeatbride.com/) that have tons of ideas for having a non-typical wedding, I love this site.