Update 09.05.2013 Since a lot of people asked about this, I fixed some issues with parallaxes in the script. If other scripts are still conflict with this one, make sure to have all other scripts about this one in your script list. Introduction Since i saw a lot of people asking for a port...
Read the instructions for the scripts - if they have specific commands to start and stop their effects, then you can use them for what you want.
If a script does not have such commands or options included, then it is almost impossible to add them later.
In case of the fog script this should be included automatically - no game has fog on every map, so you just need to follow its instructions.