Thanks for your response! I ended up posting on the EA website, and PuzzlezAddict helped me out!
"You are a genius! So just to reiterate for any other players having this issue, after I downloaded Buzzler's Fix NPC Door mod at Mod The Sims and added my playable family, I set my NPC door and moved Olive Kipling in through MasterController's Add Sim function, then I reset Olive Kipling. It showed as "nobody home" when my Sim rang the bell, but after she buzzed them at the callbox, I am able to ring the doorbell and talk to Olive if she's at home. Thank you so very much PuzzlezAddict!!!"