Point 1: Read below
Point 2: It's not a matter of portals. Or cross-dimensional teleportation. It's a matter of the fact that the Magic Mirror does literally the thing required for this. This is actually it's sole function. To escape dark inescapable areas. Because of verse equalization, Dark World and Dark Area are comparable. And if it's not considered immediate, he can easily grab the mirror to escape.
Point 3: We treat void manipulation as many things. You can be wiped from existence via being killed in the past, and we don't list that as void manipulation even though it technically is. Voiding is a broad ability. For example, Palkia and Dialga's resistance isn't the same kind of resistance as the Royal Knights, while Lavos has several void manipulating abilities.
Point 3: The transitive property doesn't work there. Just because they exist doesn't mean that it'll work on those.
Point 4: Zelda has precog, and dozens of villains didn't even need to plan around that. Link is no different to those guys. If Link stops time, he can: riddle him with evil killing Light Arrows, or turn him to stone (these only work if he's evil), he can transmute him, turn his soul into a mask, time travel and kill him when he isn't aware, seal him inside the Master Sword, freeze him and shatter him with one of his hammers, possess him, turn invisible and just plan a better strategy, or basically just attack him over and over and watch it stack. By the way, stopwatch is indefinite until Link leaves the battleground, the hourglass is a few seconds, and the Stasis Rune is a few seconds longer, but for this one, it stacks, as in if you hit them twelve times, it will register as one 12X stronger hit when time is resumed.
Source on Bubbles:
http://zelda.gamepedia.com/Curse. Turns out, there's a ring built exactly for negating this effect
Btw, you know how much I'm enjoying this, right?