How to replace or delete an area actor from a preexisting area?

Hello I am trying to replace or delete all the gnolls in the Gnoll Stronghold with remastered versions: I know how to add creatures into an area via editing an area .baf file but I currently do not know how to remove preexisting creatures from an area via WeiDU. Also the Gnoll Stronghold has random enemy spawns and I do not know how to edit those with WeiDU. I have searched through https://www.weidu.org/~thebigg/README-WeiDU.html but I am not getting much traction. Can someone please create a working script for WeiDU as an example template on how to replace or delete an actor in a preexisting area?