Connecting sfth characters from different longforms (most of these are stupid theories by me or stuff i heard from other people):
Felicity (were-cowboys) is also Maria (dfad)
Jimmy (tsotd) is also jimmy (tsp)
All mafia related characters are connected
All the lesbian characters have met up on the island of Lesbos
Bubbamiah met annabutch at some point (probably after the events of ngaag and before itmc if that makes sense)
Mr twilliger (dfad) is related to the twilligers in green leaves on a summers day
Sams character (i forgot his name) in rum and reckoning is frank from the glass eye (idk if that was confirmed) and also dr Jones and dr addams were involved with the pirates after the events of the glass eye
Maureen quickfoot is probably an alternate universe maureen (tsotd)
Obviously the luke mannings are all the same guy
Many fingers percy (dfad) is a direct relative of the O'Hands brothers/lovers
The werewolf guy in jazz vampires (forgot his name) is terrence mcavoy a long time after were-cowboys