- Acting for Two: As seen in a behind the scenes video uploaded by Evan's girlfriend, Jeff portrays both himself, and the Slender Man in Finding Fairmount. He's also the "cameramen" that HABIT summons to film everything at various points in the series, at least in the last few videos.
- Evan Jennings plays both Evan/HABIT and the Rake in the series, which is why the two of them are never seen in the same shot.
- Creator Cameo: Tim Sutton provides the voice of Roger, Princeton!Vinny's friend heard in the contents of Box 7.
- Creator's Favorite Episode: Vincent mentions in a now-deleted Instagram story that he considers Jim Thorpe to be one of his favorite episodes to film, as he and Jeff enjoyed going up to the mountains, and the scenes shot were supposedly very fun to film.
- Missing Episode: As of 2015, Alex's YouTube channel and all of the videos on it no longer exist. This is because OOG Alex deleted it due to getting a government job, and didn't want his employer to believe the videos were a real-life representation of him.
- On the main channel, "In which I assume the role of a 13 year old MySpace girl" was taken down in 2018 due to a copyright claim from WMG. Previously the audio was forcibly muted in 2015 due to an earlier claim, before being restored in September 2017. "Next" would eventually be blocked worldwide in July 2019 as well.
- Name's the Same: Contrary to popular belief, the role of "The Firebrand" does not correspond to Tribe Twelve's Noah Maxwell in any way, even if the two series have crossed over twice before. "The Firebrand" in this series actually refers to Evan.
- Old Shame: Out of Character, Evan doesn't seem too fond of the early Everyman HYBRID material. While watching Night Mind's explanation of the series, he comments on the quality with this:"Jesus Christ. Fuck. Is this what it was? Everyman HYBRID sucks monkey ass!
- Real-Life Relative: The actor who portrays James Corenthal is Evan's father in real life.
- Throw It In!: Much of Doctor Corenthal's appearance in the series consisted of creative choices Evan's dad made up as he was preparing for the role, which included his iconic leather jacket and his "shit-kicking boots". The boys decided to roll with it because it made sense given what Corenthal's role in the story was, and because it looked cool.
- What Could Have Been:
- "All good things" was originally going to end with Evan/HABIT killing Jeff, with Vinny shooting HABIT immediately afterwards, then Vinny being forced by Slender Man to swallow/shove the North Stars knife down his throat, as a way of swallowing "Justice's Sword". It was changed due to bad weather and other hindrances that prevented the creators from pulling this effect off practically.
- Doctor Corenthal's role in the story was initially much smaller in earlier drafts of the series, which had the boys only ever doing a few webcam-style chats with him on the internet. After Evan's dad got the role however, his role was expanded considerably due to him being capable of appearing in person.
- Evan wanted to use "The Thing that Should Not Be" by Metallica at some point in the series, but he was shot down by Jeff and Vinny, due to the latter disliking the band, and the former being worried that YouTube would copyright claim the videos similar to the videos that were taken down for using Frank Sinatra in them.
- There was apparently a scene filmed for ML Andersen 0 where HABIT tortured Michael Andersen after the events of "GOODBYE" where Michael was being drowned in a bathtub. During the scene, Michael acted more animalistic than normal, and apparently mocked HABIT by telling him that there was no way he would be able to stop Doctor Corenthal. This caused HABIT to go nuts and try to kill Michael instantly. This unfortunately was never released due to Dylan Sindelar having that footage, and decided to not upload it for some reason.
Trivia / Everyman HYBRID