Vizma on the GameDetectives Discord translated all of the pigpen ciphers from mattb's cleaned up flyers -
flyer1.png:
:
AOCXY SIO --ROT-6--> GUIDE YOU
flyer2.png:
:
FYNNBYNBCHANBUNM --ROT-6--> LETTHETHINGTHATS
flyer3.png:
:
GCMMCHA --ROT-6--> MISSING
These can be joined together to give the string
:
LET THE THING THAT'S MISSING GUIDE YOU