Halloween // Costume help

My boyfriend and I are going as Dwight and Angela for a Halloween party. Got our costumes picked out from goodwill and I think we’re set, however my family seems to think I need a blonde wig (I’m brunette) for people to know who I am or that we need to go as Jim and Pam. Do you think I can just straighten my hair and put a headband in or do you think I really need a wig? Trying to cut costs and really didn’t want to wear a wig all night but I want to know what others think.