Nobody raised Dirk, he was on his own from the start. 

Dad Egbert is John’s dad, the guy with the pipe and hat who baked a lot.

Fefetasprite is not mute she just never speaks directly in the narration. Roxy mentions that she spoke with her all the time here.

Since they’re paradox clones then no they probably don’t have bellybuttons. 

Sollux felt both flushed and pitch for Gamzee because of his duality theme (although his initial feelings may have been caliginous since Gamzee just killed two of his friends). Terezi felt caliginous for the same reasons. Karkat felt pale because he wanted to pacify Gamzee to calm him down. Gamzee did accept Karkat’s pale solicitation. Gamzee manipulated Terezi into killing Vriska possibly so that he didn’t have to deal with her himself. 

All of them sans Sollux had already entered the game and since the medium is in a different dimension they weren’t affected.

The Pre-scratch trolls and the Ancestors originated from the same wrigglers just like how the the Alpha kids and the Beta guardians are the same baby.

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. 

A session needs one Time player and one Space player.

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.