Hmm...not sure!
I think Vriska is more of a Perceiver than a Judger. I think Vriska is an ENTP and that Terezi is an ENTJ (based off of the odd hair-brained ideas and impulses of the former, and the insights and seer-abilities of the latter).
I think Dave is more introverted, probably an ISTP (just based off of his demeanor, although that might actually be more of his brother). Maybe INTP, I dunno.
Rose is definitely an INTJ in my eyes, due to her insights and the means with which she executes them (actions guided and determined by objective results).
Jade and John seem like ENFP and IxFP respectively; I can't quite tell if John is an N or an S though, at least off the top of my head. The reason I think Jade is an Extravert is because she seems to be, iirc, more concerned with absorbing things rather than reflecting upon them (but my memory could be at fault there).
As for the Trolls (other than the ones I've just mentioned), I'm going to suggest this:
Karkat: Not sure here. I'm thinking ESTJ like you are, because he has this constant desire to want to have control over the situation, and seems to be greatly exasperated by all the nonsensical shenanigans of the other trolls.
Kanaya: I'm thinking probably INFJ, maybe ISFJ. Many people type her as the latter, or they type her as a Thinker, but the reason I'm thinking INFJ is the somewhat aloof and detached way she views reality (which is common in Ni-doms), yet the value she places upon the needs and overall mood of the 'group' as a whole (Aux Fe). Also, the nature of her eclectic interests seem to be symptomatic of an Inferior Se; we're often very drawn in by details and the various 'finer' things in like without being aware of it.
Eridan: Reeeeally not sure here. I was thinking INTJ?
Sollux: I'm thinking ISTP; I used to think INTP, but I realized he's a little too concerned with the present and current circumstances to have Aux Ne. He definitely seems to have Dom Ti, though.
Feferi: I think ISFP; I know it seems strange for me to type her as an introvert, but there seems to be a greater degree of Introverted Feeling involved in my eyes, and her Extraverted Sensing seems secondary (with Tert Ni, especially seen in her rationale for 'breaking up' with Eridan as moirails).
Nepeta: I...have no clue here. She seems like she might be Dom Ne, so ENFP? *hides*
Gamzee: O_O No. Just no. ESFP?
Equuis: Hrm...ISTJ?
Aradia: I'm...not sure about her. She never really interested me as a character, oddly enough, so Ima let other people tackle this one.
Tavros: INFP. I'm pretty sure about this one.
(Just to throw these out there for other stuff: SPOILER ALERT)
Aranea: ENFJ
Meenah: ESTP
uranianUmbra: ENFP?
undyingUmbrage: ENTJ?
Roxy: ESFx?
Dirk: IxTP?
Jane: ISFJ?
Jake: INxP?
