Looking to run howling horde in PF, all players seasoned camera two are normally DMs, think they are expecting a straight up run thru. Thinking of changing it up and adding a twist. Replacing half CR 1/3 goblins with CR 1/3 drow, changing other half into goblin skeletons and zombies, Hob wizard as drow necro and changing out CR 3 black dragon for CR drow noble cleric. Trying to make it look like original lair was taken over by drow invading party. Instead of initial goblin attack in beggining having three drow with ancestral regression spells up. Additional ideas or tips are greatly appreciated. And thoughts on change up in general.