StanLemon

Except the Shroud stops existing at the end of the book. It's like saying a Returned who has used their Divine Breath is still being kept alive by that Divine Breath that doesn't exist anymore. All Cognitive Shadows we know of need something to hold their physical bodies. There Heralds need the Oathpact, Kelsier needs his Spike, the Returned need Divine Breath. Yumi doesn't have that limitation With the Shroud dissipating at the end, it's not there to hold her physical body. I agree with you that her regrowing a body isn't any different than Investiture healing, but I think it's fair to say she's not a Cognitive Shadow anymore and truly came back to life

I'm assuming she's a flesh and blood human again. All the other Cognitive Shadows we know of need some kind of "tether" to have physical bodies like Kelsier's Spike, The Oathpact, Divine Breath, etc. There's nothing like that even hinted at to be the case at the end of the book

Here is a thought, maybe it's related to how younger Breaths are better than older Breaths. It could be linked to the life force of the user

Ah, my apologies then. The last time I had read that page, the part about the newest edition retconning that hadn't been in the Coppermind.

That's exactly what I'm saying, none did. During that conversation Elend thinks to himself about the standard Spikes an Inquisitor has and is surprised that there is an extra Spike in that specific Inquisitor. And he's surprised when it's Pewter. It wasn't until the reveal that it is a Pewter Spike that they even start thinking that it's a third power from Allomancy and Feruchemy because he starts thinking about how Allomancy and Feruchemy use different metals for different effects. None of Elend's line of thinking makes any sense if any of the Inquisitors in Kredik Shaw had any Spikes other than Steel or Bronze

He couldn't have had F-Gold for one very simple reason. The only Spikes that Vin or Elend had seen from any Inquisitors before HoA were Steel and Bronze. This means Kar could not have had Feruchemy

I'm personally a fan of A-Bendalloy and F-Steel as a Twinborn combo

Considering Inquisitor's are described as aging slowly and living longer, Spikes do no cause faster aging. It's more likely that those that 'burn up' are simply overtaxing their bodies like someone who does too much labor breaks down their body. Also, though it might be an effect of Pewter Allomancy boosted by Hemalurgy, Kar the Inquisitor that Vin harmed and was fully healed by the time she next saw him only hours later could not have had Feruchemical Gold so he clearly had a higher healing rate than a normal person rather than a reduced rate

There's the character named 16 in Rhythm of War

I very much would love more A-Gold in the books. Your reference to Everything, Everywhere, All at Once is how I often have viewed how it could be used. In fact a few years ago me and my group played a MAG where we let A-Gold be rolled for that exact effect giving Traits for my character. My inspiration for that though was from Emperor's Soul and the use of Soul Stamping. An alternative life you could have lived with skills you could have developed.

Brandon has made a comment that Steel/Iron burn quickly but Allomancers generally don't notice because they aren't Pushing all the time. This implies to me that burning it for the blue lines is slow but burns faster when actually Pushing/Pulling. This would be in line with his comment about burn rate being tied to how much work the Investiture is doing. As to your second question. Weight matters, but it isn't the determining factor for strength of Pushes/Pulls exactly. Think of the blue line as a force acting equally on both the Allomancer and the metal. When a Coinshot Pushes, the force is Pushing against the Allomancer and metal identically. Per Newton's 3rd law, any action has an equal and opposite reaction. This leads to a greater amount of net force being applied to the lighter object which then moves away from the heavier object. As far as your third question goes, I personally think that it doesn't require burning any more Steel or Iron. The greater mass of the metal seems to naturally translate to thicker blue lines that can be seen at greater distances. In effect a Coinshot would be Pushing harder off of it, but that's more of a consequence of the greater net force acting on the Coinshot

Additionally he has said they are more flexible than the medallions

A sword used by a 5 ft Koloss was so heavy that Elend barely could lift it. As Koloss take larger swords as they get bigger this would imply that a sword used by a 5ft Koloss is at least the approximately the size of a claymore if not even heavier. As far as their strength goes in general, during the siege a Koloss throws a rock with enough force to hit a soldier, crush his face, and still have enough force to throw him off the wall. I've been on the top of defensive walls before and it would have to knock the soldier several feet backwards to do that. That implies a great deal of strength

So a gorilla is anywhere from 5-10x the strength of a person. Answers i found from Google varied but were around that range. From muscle mass alone I could see a 12 foot Koloss being at least on the lower end of that scale. Add in the 4 Iron Spikes extra strength it's probably safe to say that a 12 foot Koloss approaches 10x human strength even if not quite reaching it.

Oh I'm sure that they aren't, just that they are indeed stronger that their size would imply. Considering what is shown in the books, a 5 footer is probably around that strong. Though Vin never does match a Koloss strength for strength which makes it hard to judge. But considering that she uses a sword longer than she is tall, it would require a massive amount of strength. Zweihander's which are of comparable length are really really heavy swords