So I've been playing x wing for about 3 months now and still unsure about evade tokens adding an evade dice to your pool of dice. Now it's my understanding that, for instance, if you have ten numb with a mangler, the hit that gets changed to a crit is unblockable even by a token? Am I doing this correctly, also, what don't evade tokens cancel out?

evade tokens can't be used to cancel hit results with autoblasters and autoblaster turrets (can be used to cancel crit results)

Homing missiles also prevent the use of evade tokens

any damage that is not the result of an Attack - i.e Darth Vader, Prox Mines, Bombs, asteroid collisions etc etc

The easiest way to look at it to me is that you can only spend an Evade token whenever you'd get to roll defense dice (not when rolling green dice to determine if an ability works). When you spend the Evade token it becomes a green die that has rolled an Evade result. This die cannot be modified but may be canceled. From that point forward, you treat it the same way you would a green die.

Any abilities that prevent you spending an Evade token will call that out. As far as I know, any time that you are allowed to spend an Evade token it works just like an Evade result.

WWHSD has it right. Spending an evade token occurs during the "Modify Defense Dice" step of the Combat Phase. Spending that token adds an evade dice result to the pool. Therefore, any ability that blocks canceling attack dice via evade results (such as Autoblasters or Ten Nunb) won't be affected by an Evade token expenditure.

Furthermore, the die added via the Evade token can be modified further...but only by the defender. Wen defending, the attack modifies defense dice first, then the defender; spending Evade tokens happens during the defender's sub-step, so any opportunity the attacker had to modify that particular result has passed. Timing is important.

Furthermore, the die added via the Evade token can be modified further

This is incorrect. Per the FAQ, pg 8 (emphasis mine):

Dice Results

Results that are added are treated as dice results that can only be canceled

(they cannot be modified or rerolled). For example, when attacking with

“Autoblaster” a [evade] result added by an evade token cannot cancel a [hit] result.

Furthermore, the die added via the Evade token can be modified further

This is incorrect. Per the FAQ, pg 8 (emphasis mine):

Dice Results

Results that are added are treated as dice results that can only be canceled

(they cannot be modified or rerolled). For example, when attacking with

“Autoblaster” a [evade] result added by an evade token cannot cancel a result.

You're missing the [hit] in the last sentence.

when attacking with "Autoblaster" a [evade] result added by an evade token cannot cancel a [hit] result.

Right you are, I'll go edit it to fix. I caught one of the places where copy/paste missed the icon but missed the other. Proofreading fail.