The scratch is a release of temporal energy that causes Skaia to switch which portals the meteors go through. It results in a reset universe and a switched set of players. The scratch was always necessary for the alpha timeline so it didn’t affect any other timelines. 

Yes, you can ascend to godtier if your dreamself is dead, you just have to use your Sacrificial Slab and not your Quest Bed. Everyone who has gone godtier has reached the top of their echeladder but it has not been stated outright if it is a requirement to ascend.

Yes Roxy does canonically have a crush on Dirk. She states that she loves him on this page. 

The Condesce destroyed the moon so Dirk and Roxy could ascend to godtier.

Here you go.

The Vast Glub was a psychic shockwave released by Feferi’s lusus that killed every troll in the galaxy except the trolls with fuchsia blood who are Feferi and the Condesce. The Vast Glub was released right before Feferi’s lusus died. 

Right now the canon ships are as follows:

Terezi <> Vriska

Punk!Vriska <3 Meenah

Mituna <3 Latula

Meulin <> Horruss

Spades Slick <3 Ms Paint

Nepeta <> Equius

Kurloz <> Mituna

Rose <3 Kanaya

There are three kinds of bad sessions: null sessions, dead sessions, and void sessions. An example of a void session is the Alpha kid’s session. A void session is when nothing is prototyped pre entry. This means the battlefield cannot evolve and grow and the session will go on forever because the Black and White king’s war will be an eternal stalemate. 

Feferi’s lusus was implied to have been killed by a meteor after she released the Vast Glub. She then fell into Feferi’s kernel sprite and was prototyped. 

Either Jade or Bec but it was most likely Bec since a young Jade probably couldn’t have brought herself to stuff her own grandfather.