While grouping things by wording is a sensible first approach, the ambiguity of the english language makes it (I think) not the optimal one. This is evidenced by the fact that "would" is use for effects in both step 5 and step 7 of my ordering.
Which is why I explained both meanings of "would." 
However, Null-Point Iso is exactly why I did it that way. Both have simialr wordings, and just looking at the texts should dicate the timing, not the interpretation of the cards. However, you could go either way. One thing you did miss was to see if damage "would be dealt" after modifications but before redirecting.
Alright, I understood it correctly then. I was using card semantics innapproriately to try to justify the exclusivity of the effects.
In a perfect world, yes, but we don't live there 
Do you know of an actual case for "would be dealt" that should happen "after modifications but before redirecting"? All the cases I can think of off the top of my head either work out to Prevention or Redirection, which happen in the same sub-phase.
If no damage would have been dealt, then there is no redirection. NightMist can't redirect while is Mistform, since there is no damage to redirect. After all modifications, you still have to check to see if there is potential damage, if not then there are no other effects. This was another reason why I grouped it that way. You still have to check for hp loss in each case, but cetain things, like rediction and Null-Point, will change that hp loss into something else.
I've edited my listing to make it clear that steps 3 (which covers Mist Form) and 5b can halt evaluation. Am I still missing anything?
Since Prevention negates redirection, it should come first.
I think you're assuming the outcome you want. What makes "prevention negates redirection" more valid than "redirection negates prevention"?
In the case I'm most familiar with (Undaunted + Smoke Bombs), obviously only one of them can happen, but it's not clear to me which one should. And indeed, the App lets the player choose in this case.
It would be plausible to put prevention and redirection into separate categories and put those categories in a specific order, but that doesn't seem to be what Christopher wants.
step 0: can damage be dealt by the damage dealer?
If both trigger at the same time, it's entirely up to the players to determine the order. And, in fact both can trigger. If a villian is dealing 2 damage to the hero with the highest HP and that hero is Fanatic, Smoke bombs can easily redirect it to her, reduce it by one, and cancel it out entirely.
Unless I'm misunderstanding your question?
I was thinking of the situation where Fanatic is *lowest*, and is getting hit by 1 point of damage. Whichever of Undaunted/Smoke Bombs triggers first, the other won't then be able to.
Essentially the same choice between Iso and LftF. Only one works.
Added to my list, thanks.
Actually, if you want EVERY step it is a bit more complicated than that. Will type it up once I can get to a computer.
Whichever happens, the resulting damage will still be zero, so… How does it matter?
Because the highest HP could have nemesis bonus, Bloody Knuckles, Glass Jaw or any number of other damage increasing effects on them, redirection via Smoke Bombs would be painful.
The answer matters, but I don't know what it is.
At first, I was going to take this really seriously, but then it got to 20 steps. :) So, I am leaving it up to everyone here. Edit this spreadsheet and see how far we can go.
EDIT: Thanks to the great Matchstickman!
The editable spreadsheet is at this link.
https://docs.google.com/spreadsheets/d/tZfiNqJyV3rK-QAsuSFG33w/edit#gid=0
Fair enough
Well according to the first post and that spreadsheet, seems like damage redirection happens after modifiers and/or damage nullification
So you would use Undaunted to reduce damage to 0 before Smoke Bombs triggered in my opinion