I think there's a short window where the molotov could be thrown through the window in Freddy's Dead during the first episode. Perhaps the Dream Demons go into Freddy after telling him that he will be immortal, he thus survives the first fire, then the mob go inside the power plant and he's set on fire again which is when he dies (at that point he knows he'll survive). Also, he was taken to court in 1966 and 1968 to explain the different reasons he was allowed to walk free.
I like how in Sister's Keeper, they comment on how a character is from the 60s... which was only 6 years ago? I mean, they're not technically wrong though.
Okay, so... Freddy graduated in 1970 (wtf?) according to Freddy's Nightmares, and 20 years later he massacred his high school reunion. His high school friend, who he let live, went on to give a script to Hollywood which was turned into a film known as A Nightmare on Elm Street.
However, it is something that can be ignored apparently.
So... uh... maybe it's actually the class of '60 and 20 years later places that episode in 1980? You know, this show would work so much better as a prequel set before the first film. That site places it in 1991-1999 to bridge that 10 year gap between the 5th and 6th films though, so... it's kind of a crap situation.
2x12 does give the origin for the in-universe A Nightmare on Elm Street film series referenced in Evil Dead Rise and the Hatchet comics technically speaking (going off of Slasher connections), so it's nice that there's a bit of accidental continuity flowing here.
Also, so many fictive layers here!
Layer 1 - Real world
Layer 2 - Wes Craven's New Nightmare
Layer 3 - A Nightmare on Elm Street film series
Layer 4 - A Nightmare on Elm Street in-universe film series
The Pamela Tapes say Jason was 12 when he died (born in 1945).
Jason Goes to Hell says that Jason was born on June 13, 1946.
The Pamela tapes say Jason was "10 years old yesterday" (born in 1947?).
Pamela's Tale places his birth in 1948.
So... what the heck is going on!?! Lol
I'll use the films as a priority. It's pretty much in the middle anyway.