Most Paradox Space comics are not necessarily canon to the main timeline. Except for at least “The Inaugural Death of Mister Seven“ and “Vrisky Business” which Andrew Hussie wrote

Given those two’s relationship and individual personalities,  I’d say that any flirting had to be at least 80% ironic

Possibly? It is a prequel spinoff so I don’t know how much it could affect the main story but you never know, it could explain you a thing or two

Nepeta, never got to go out on a date : (

Universe C is the universe created by the kids’ session. They also took B2 Earth to Universe C which eventually became home to the Cali twins. The Earth doesn’t go through a Black Hole until Caliborn starts his session and it just goes to his medium.

Equius! As for why, I think there was just something about a creepy kid that no one really liked that 16 year old me was really drawn to and he’s just stuck with me since.

Also when I say no one, I mean no one. Equius was like the least popular character back in 2012, there was next to no fan art or anything for him. The same thing could be said about Nepeta. It wasn’t until the short lived late-2012 memes of “with Equius” and “Nepeta’s dead” that the fandom as a whole started to appreciate these beautiful children.

I don’t know about the Ring of Life, but I know she said she’d like to give the Ring of Void to the person she was going to marry

Mspa search feature is very handy and for stuff I can’t find with that I usually have a pretty good idea of where in the story it took place to use as a starting point

 but I guarantee you it is not all easy. Some posts I have to spend 15, 30 minutes finding the answers to, hell I’ve spent a good hour and a half looking for answers before. Typically the longer I spend looking for an answer the less notes that post gets lmao

I consider any part of Homestuck not done by Hussie to be semi-canon. 

Guest artists are going to have their own biases and preferences reflected by their art which I feel is a product of but also goes against Homestuck’s ideology that all the characters are essentially blank slates that the readers can interpret in any way they like. 

Instances of Guest Artists using personal interpretations of characters (in these cases Karkat) can be seen in Collide and Game Over. In Collide when we see Karkat dual-wield sickles, but that’s the only time we ever see him dual-wield. Or in Game Over how Karkat is animated having short sleeves when we have always seen his outfit having long sleeves.

Like Steven Universe, Homestuck allows its art team a full range of creative control with how they draw characters, and there’s nothing wrong with that, it just lets certain content get into the comic that wasn’t laid out by the Huss-man himself.

So to answer your question on how much of the credits/snapchat content I view as canon; All of it, in varying degrees.