Initial thoughts:
Okay, I readily admit that I don't know much about the apostles. But, looking up their names, I noticed a couple of Simons and a Thomas. It's Halloween, so maybe Simon Belmont, something to do with Castlevania. Thomas means "twin." Timmy and Tommy are twins. I tried typing TIMMY and TOMMY and NOOKLINGS in the DEF redemption thing. Also tried SIMON, BELMONT, SIMONBELMONT, and CASTLEVANIA.
That's all I've got at the moment, I haven't found anything yet. But I'm still looking and thinking.
Those are ideas I had, maybe they'll inspire someone to find the right answer.
EDIT: More research has shown that apparently
John is considered the missing apostle. Something to do with Da Vinci's Last Supper painting. I don't fully understand it. But that's some new information I found. I didn't see anything in this thread with the Last Supper recreated in Animal Crossing, but I could have missed something. https://www.belltreeforums.com/threads/harveys-feast-community-voting.604576/
Also, please forgive my ignorance if I relate some information incorrectly regarding religion, I want to be respectful but don't understand all of it. ^o^;>
EDIT EDIT: I really hope someone more knowledgeable on the subject posts something soon, I feel like I might be completely wrong and can't tell. I don't want to be accidentally misleading or offensive or embarrassingly off the mark.