They are possibly there via a memory of them that John or Rose has, but the exact Mom and Dad that were killed by Bec Noir are not

He once made his own Auto Responder, Lil Hal Junior

That’s debatable. I don’t see it that way but if you’d like to that’s okay.

All actual “fact” posts are tagged with the character’s name.

As for in asks, I can try. It’s been attempted in the past but never sticks for very long.

The search feature on the blog can be helpful too if you’re just looking for things that include a certain character

Readmspa.org’s search function is useful, as is mspa’s own search feature. The wiki is a helpful tool aswell

It’s to show that they were cloned. Hussie stated in an old Formspring Q&A that all Carapacians are cloned aside from the Kings and Queens and thus have the tattoo. 

It’s stated right in her intro, but we later learn she didn’t actually have narcolepsy, it was just Vriska testing her powers out on humans

Hussie has said a lot of things jokingly in his Q&As such as the Squiddles thing and Sollux being short for Solluxander

She has not, at least that I’m aware of

The Peixes are related to the Prospit kids and their Guardians via Adoption, not ectobioology. They aren’t any Troll/Human hybrids walking around that we know about.