My question is short and simple.

Assume a normal, 50 minutes timer is set for a Constructed tournament round.

Assume the timer runs to completion.

Assume that a player is in the middle of an action, having just declared said action.

1: Is the player allowed to finish the action per WizKids' official tournament procedures? Is there even an official setup for this?

2: Otherwise, is the game supposed to go to the end of the player's turn (or to the end of the overall round), or is it supposed to be over as soon as time is called?

All I can find regarding this on the WizKids Rules Forum is as follows:

Victory Conditions: When one player is eliminated or the time limit is reached. If the time limit is reached, the player with the most KO points at the end of that round wins.

However, an article elsewhere on their site (Gameplay > Formats > Constructed) reads as follows:

When a player’s force is eliminated or the time limit is reached, the game ends. If the time limit is reached, the player with the most KO points at the end of the game wins.

Note the difference in "end of that round" and "end of the game."

Thank you for your time.

The second quote you have is referring to the round of the tournament, not the round of the game.

HCR had a big discussion about this about six months back and upshot involved ROC changing its rules, but there was no real consensus. So ask your judge. If you're asking because you started at new venue and your new judge does things differently, that's normal.

If you go to an official WK tournament at, say, Origins, then time is called by saying "Last action."

This means that any declared actions are taken to completion, then the game ends.

So if I have said "Shemp is going to use Multiattack." immediately before the judge calls "Last action," then I get to do everything within that multiattack before the game is over, but that is all that happens.

My venue allows players to finish the round, so ideally whoever is running behind on points has a chance to either save himself or tighten the points gap.

A couple of things here...
1) The OP was asking for the official policy, which this is definitely not. The official way is as I mentioned above. Last action is called, and you resolve any declared actions. (To be clear, if no action has been declared, you do not get one more action.)
2) While some people will swear on high that this way is wonderful, it is actually a terrible way to do it. The reason is because it completely changes the dynamic of the game because all strategy goes out the window when there is no fear of reprisal. Under normal circumstances I'm not going to send my HSS his full speed out into the midst of a crowd of opposing characters and let him sit there, but if I know that I can do it without you have a chance to strike back, yeah, I'll go ahead and do that.
For the same reason, it is also terrible to continue the round until player two completes his turn.

The only way to end a timed game and maintain the integrity of the game is to do it in the official way. To prevent gaming the clock under their system, WK allows a five minute swing on their rounds, so your 50 minute game can last anywhere from 45-55 minutes. Even when calling out the remaining time, there is wiggle room left by calling "about half way" or "about 10 minutes left" at those points.

Thank you! That's the way I've judged things for about 14 years, but I've heard of other ways, and I couldn't find this in any documentation on their site when I searched just before posting this thread.

So, yes, I am the usual judge, and, no, this isn't a new venue. I am, however, a stickler for doing everything by the book.

Is this setup in any official documentation, for that matter?

There used to be a page for the tournament procedures, but I don't think that they've been keeping it up. IIRC, they posted one last year before the cons, but then it went away again.

I'm sure that you can probably find a copy of the old tournament rules document with a little digging.

That is the Official Way at big WK events, but there is NO Official Way.

While having some imbalances, there is nothing wrong with that way. The concept of the last player getting to take his last turn is FULLY supported by the rules.

I am in the "last action" camp but am completely Undisturbed by any other method as long as I am aware of it before I start building my team as It may affect my selections.

Indeed as Harpua mentioned the last player in a "play to the end of round" format can have an advantage at the end of the game. So you may want to emphasize Themed Team to enhance your Starting Player Roll so that you can make a choice as to which player you might want to be.

I would really like to know where you're getting that idea, because it certainly doesn't say anything like that in the rule book. The entry in the rule book technically doesn't even allow you to finish actions once time is up, so quite the opposite, in fact.

And the Tournament Rules just say-
And yes, because "Last Action" is what WK's uses for their events (despite not having it in their documents), that does make it the official way to do things. That's like saying their rulings aren't official because they only really matter for WK events, and there's nothing forcing individual venues or players to abide by them otherwise. Venues are absolutely within their rights to do things differently, but the official way is whatever WK's says it is.

My venue doesn't say last round/action. 'Dice down' and add up points immediately. No opportunity to change an action or roll dice although attacks declared before that can be resolved.

I ran tourneys with last action for about 3 months. There were so many gripes and complaints on stalling and running away (back when surviving points also counted) that I simply switched to calling a 10-15 minute warning ONCE per game and allowing for a full round IE both players getting an equal amount of turns.

I can count on one hand complaints since. First player can complain that the 2nd player got a chance to catch up but have a 10-15 minute head start knowing you may not be going last is what you can plan around and vice versa.

Last action is kinda janky and 50% of the time end on a sidestep nowadays LOL

How does last turn solve running away? If I am determined to run away from my opponent, I will do so, whether I've got 10 turns left, 1 turn, or no turns.

There are definitely arguments that can be made for giving each player an equal number of turns, but this is the first I've ever seen some one argue that it prevents running.

If anything, last action solves it better: If I *KNOW* I've got one more turn to get away, I may choose not to push since I can always act next turn. If I am not sure if I'll get another turn or not and I am worried my opponent might catch me, I'll definitely be more free with the pushing.

And if stalling is a complaint (and it's REALLY stalling), then that's cheating, period. Doesn't matter what the format is: don't stall or there will be consequences.

There is an option to play an event by a fixed number of rounds which is just as official as having a set time for the round.

With the option for a game to be played by a set number of rounds essentially the same imbalance remains favoring the last player in the last round as the last player on his last turn has zero repercussions for taking otherwise risky actions.

So the question becomes is that imbalance either not that big of a deal or potentially offset by other elements of the game such as the imbalance of being able to go first and attack first.

From the WIN

12. We will not answer questions on how a venue should run local events (including Organized Play events). Venues are free to run events as they see fit. OP events are suggested formats and do not have to be run according to the suggested format unless specified otherwise. We also will not answer questions regarding events using special scenario rules. Those questions must be answered by the judge of that event.

Ultimately this may just be an argument in semantics as any event run exclusively by WK by definition will follow the way WK runs events.