Nitpicking

They don't. Why do you assume T. is overthrown or destroyed? SPOILERS for the greater Cosmere:

I don't have Wind and Truth with me here, but didn't Retribution say he was going to inhale all the spren? Would that not include the Voidspren? The Voidspren were saved from being incorporated into Retribution as nothing but a source of Investiture by the Heralds and the Wind. And potentially, partly by the human and Singer freeing of Ba-Ado-Mishram. How will that affect their attitude in the Back Five?

We know that Enlightened Radiants (like Venli) can use Voidlight for the Surges. I expect they can also use Warlight.

I'm trying to avoid spoiling by implication, so I'll spoiler-hide the title:

I would argue that Dalinar's death is a fakeout, too. He's dead, but then the Blackthorn spren is young Dalinar. It's a cheat. I'm sure Brandon will use it to explore the Cognitive Shadow concept. Is that really Vasher, or a spren with Vasher's memories? Also, don't forget both Tanavast and Honor, who we were led to believe were dead. EDIT: SPOILER FOR A SECRET PROJECT

I would think microkinesis, but we only know a very few practitioners of that Invested Art.

I wonder how specific an "ability" is, that you can spike out of someone. If you formulate your Intent perfectly, can you spike out the ability to reject organs, thus making transplants incredibly easy? You could just let the spike "decay" and lose the ability to give that ability to someone else, nobody wants to be able to reject organs, it's an unwanted side effect of the ability to fight off infections.

The bit Jult highlighted is: " He will have to abide by those terms, as they are part of the promise Rayse made by taking up the Shard of Odium." One thing we know all the Shards are bound by: if they take an oath, violating it opens them up to being destroyed (splintered, the Vessel killed). Odium (who is pretty honest before Taravangian takes over) told Dalinar this, that if he broke an oath Cultivation could just kill him (in revenge for the killing of Tanavast).

Towerlight is said at the end of WaT to be available, but only in and very near Urithuru, and it can't be stored in gems because it leaks out quickly for plot convenience reasons. It's implied that only Radiants bound to Enlightened spren or Voidspren can use Voidlight. Venli comments that she can use Voidlight for Surges "because" she also has a Voidspren. (She also keeps her Envoyform abilities, such as speaking and understanding all languages.)

Wait, why did I spoiler that? This is a spoilers-allowed zone. Well, in Elantris, we see Raoden doing exactly that after what, a few months of practice? And the other Elantrians mostly have far less. So the answer is: why would a story about magic writing on an alien planet be realistic? In Tress we have two people who are both thousands of years old, so they have even better reason to be able to do it.

The Radiant Honorspren might not be willing to get close to Lasting Integrity, considering how abusive the current junta there was. Being captured could have been very bad for them.

SPOILERS FOR ONE OF THE SECRET PROJECTS

Cosmere spoiler answer: The whole "Yoki-Hijo are special" thing is and always was a lie (or arguably just a misconception). They become special by what they do, but anyone could call spirits if they became good enough artists. Painter does it!

Exactly my reaction.

Who says Hoid is using the Dor? He has all that Investiture from the Dawnshard.