>Who is the "master" that Aradia and Dave serve?

In context Aradia is referring to the existence of doomed timelines, and the fact that they, as time players, have a better understanding of said doomed timelines and the consequence of said doomed timelines (i.e.: death). At that point of the story, it's likely the reader will assume that when Aradia says "master" she's speaking more so metaphorically (Dave refers to a undefined "time god" in the next line), as doomed timelines are understood as just a reality of paradox space or whatever at that point. However, in retrospect, we can assume the master in question is Caliborn/Lord English, as he is the lord of time and it is implied/speculated the concept of the alpha timeline exists specifically because the alpha timeline is the one that facilitates his birth (Calliope states that a part of his role as the lord of time is the fact that things just work out for him).

>What's with fedorafreak? (pgs. 3954–3956) Is he from Universe B1? If so, why are there 4 heroes and not 5?

There are a ton of different sburb sessions happening at the same time (in the page where Rose looks at the map of the meteors, sorry can't find the exact page rn, you see that there are a ton of active sburb sessions and meteors are hitting specific places where people are trying to enter), it's just that seemingly the beta kids' session is the only one to succeed. This makes sense since sburb is a regular released game in Universe B1, and also mirrors the idea of sburb being a reproduction system for universes: there are a lot of attempts, but only some of them are fertile.

>What is AltCalliope's promise to Echidna? (pg. 7616)

The choice the denizen places upon a person in a one-person session is to either become a conqueror (Caliborn chooses this) or a martyr (Calliope chooses this). When this choice is introduced, it is also said that someone who chooses martyrdom will likely use the power granted by their denizen to later down the line defeat/stop someone who chose conquest, so most likely her promise was to defeat/stop Caliborn, which she goes on to do with the black hole.

>Why can't The Condesce mind control Vriska? (pg. 7520) Why is she resistant? She's from a lower blood caste.

It's not actually stated that mind control works on "lower castes", but rather the "impressionable" (pg 2178). I'm pretty sure Vriska can't mind control Aradia, for example. The point here being that it doesn't depend on caste, but mental fortitude. This is also why Vriska can only control Sollux half the time - since he's bipolar, he's only susceptible to it during his episodes.

>What exactly is going on in [S] Terezi: Remem8er.?

Terezi is remembering! Lol, but actually: we are shown several things. Firstly, Terezi reminiscing on her childhood with Vriska. Secondly, we are shown all the instances of ghosts waking up after their deaths in the dream bubbles. Thirdly, we are shown Terezi from the game over timeline and (Vriska) using dream bubbles to find each other and reunite. Since dream bubbles work on memories, it's my read (and I'm pretty sure it's what was meant to be conveyed) that both doomed Terezi and (Vriska) are remembering their times together, which results in their paths through the dream bubbles converging and they find each other.

>How was PM able to resist/attack Jade? Why couldn't Jack do the same? (pg. 8087)

It's pretty much implied that they don't have the resistance to actually "hurt" Jade, they just can't kill her/meaningfully harm her because of the Bec influence. PM just punches Jade to temporarily knock her out (and since she's a god at this point the attack doesn't meaningfully hurt her). In terms of character motivations, I think the reason Jack couldn't do the same is because Jack is a murderous asshole who's entire motivation is blind murder, especially since by that point Bec Noir has murdered universes for basically no reason. PM, on the other hand, doesn't want to murder anyone, just stop Jack, which is why she's capable of making a momentary pragmatic decision to non-lethally incapacitate Jade, something Jack cannot do because he's basically permanently running on murderous intent.

>Why is Jade blonde? (pg. 4855)

She's an old woman so her hair went grey/white.

>Why does Snowman have blue blood, while the other Dersites have red? (pg. 4110)

Because she's tied to the troll's universe (as in, she literally has that entire universe inside her), which is represented by blue in [S] Cascade. So she's literally bleeding out the universe.

>"When you think so little of yourself as a moral character, any act of self-termination will result in a death that is Just." ???????? He's not the one making the judgement???????? Why should it matter what he thinks about himself???????? (Candy, pg. 14)

This one's a bit complicated but my personal interpretation is the idea of the fact that he is both the killer and the victim - and he chooses to kill himself in the most public, gruesome way possible. The passages before this describe just how gruesome his suicide was, so I think the idea here is that he's so unconcerned with his life and the way that it affects others that his suicide is "justice" for him. as opposed to continue to exist as a person in this world despite him thinking that literally nothing matters anymore as far as his existence is concerned makes his suicide just. Of course this comes with the caveat that the whole godtier judgement thing is muddled on purpose in the first place, and that the whole idea of "just" is more complicated than it seems on first glance. But yeah I think the idea here is that if he thinks there's literally nothing that matters in regards to him existing within this narrative, the narrative considers it just for him to take himself out of it.

>Why do John's retcon powers stop working in the Candy timeline? He's unburdened by Canon, no?

I think the idea here is that the concept of a "retcon" only even works as far as you're working with a canon to begin with. Like, when we look at what a "retcon" is in terms of definition, it is going back on something said previously and stating contradicting information, basically changing the canon. So if you're outside of canon, there's nothing to change. He tethered himself completely from what needs to be done in order to continue staying within canon (in this context: completing the Caliborn/Lord English timeloop), so he loses his ability to interact with canon (which is what the retcon powers do).

>How the hell are Jane and Jake on the ship w/ The Meat Gang? Did Vriska just yoink them from Midnight city and put them there? If so, why doesn't Karkat react more strongly to their presence? He acts like it's no big deal. Were they "already there," so to speak? How? Why did Vriska put them there?

It's heavily implied and currently speculated that Vriska has gained some sort of retcon powers (highlighted by the dialogue right before this happens). Meaning, Jane and Jake being there is a retcon, hence why Karkat reacts like it's normal.