Are the lost tapes in the Fog and are nonteachable perks once teachable?

I really like reading the flavor text for perks and items and what not (my favorite is "You call these tools? ...Really?") and for some items they bring up unique character items. Like Donna's Sketchbook (The fog is alluring. I love it and hate it at the same time) or The Lost Tapes. And honestly every time I read them, I think, "Are the lost tapes actually from the Fog?" All the quotes are very vague. "Buckle up, fuckos! Let's roll" on hope from Nicki I believe and "Take it from an old timer, live slow and die old. The best way to beat him is to know how he thinks." from Murf, I wanna say on Dark Sense. So are these lost tapes able to be found in the Fog? How would survivors play them without any device? How would they have been recorded? On the subject of these tapes, they are flavor text for nonteachable perks, which are available on every single character. So that made me think, were they at one point teachable before Murf, Donna, Nicki, (assuming Nicki and Murf were ever in the Fog to begin with) and whoever else lost hope and fell into the void? Because once you unlock a teachable, essentially the other survivors tell each other how to do AKA teachable perks. They then become available on the bloodwebs of every survivor. Like Hope, Dark Sense, Deja Vu, Spine Chill, and on and on.

Also how do killer teachables work because devs have said that killers do not interact with each other outside the trials (including Legion i guess)