The recent thread on Meera at LCG Days is just an example of how the lack of ruling in "Then" effects leads to confusion. Based on what we know, we should be able to agree on something.
TIMING
From Nate French:
"For a "then" effect to resolve, the pre-then aspect of the effect must have successfully resolved.
This means that Meera is in play by the time the "then" effect resolves, so that aspect of her effect qualifies as a character ability."
From the FAQ (3.38) : Saving from "Then" Effects
"Any "Then" effect that would remove
a character from play creates a special
opportunity for players to play “save”
responses to the terminal “Then” effect."
So, "Then" effects resolve around Step 3) of action window.
I personnaly think it cannot resolve inside Step 3) as a part of it, because the effect must have been successfully resolved, and we only know this After Step 3) has successfully resolved.
So it must be after Step 3). The "Then" effect may have cost and play restriction, which are typically dealt with in an initiation phase - that could be called Step 3.1). There is usually no Save/Cancel opportunity for "Then" effects, except that §3.38 defines a Save opportunity (but no Cancel). That could be called Step 3.2) Save Response. After that, the "Then" effect resolves, which could be Step 3.3).
Note that this timing is general to all player actions, not effects involving directly a "Then" effect. As a matter of fact, a "Then" effect can initiate during any action window. An example is "The Gift" "The Neck" errata (v1.3) that says the Then effect only occur (initiate) when a card of the specified type is played.
EFFECT TYPE
Now about the effect type, we know the following from Nate :
"Death by Payne responds to the entire triggering of Meera's effect, not only the "then" aspect of it. Since the effect was not triggered as a character ability, the card Death by Payne cannot be played in response to her. "
"When she chooses targets for her "then" effect, Meera is completely in play, and this aspect of her effect resolves as an ability. Viper is immune to her "then" effect."
So we can guess that a "Then" effects' type is defined during its own initiation, not during the whole effect initiation. I have seen on the boards that one may argue the "Then" effect is no longer related to the character and just part of the triggered effect that has initiated. So on this we know that FFG has ruled otherwise : when a "Then" effect initiates, its type is impacted by the card that has initiated the effect. So the draw effect of "The Gift" is a location ability, for example.
CONCLUSION : THE PLAYER ACTION WINDOW
1. Action is initiated
2. Save/Cancel responses
3.0. Action is resolved
3.1. "Then" effects are initiated (Order chosen by the First player)
3.2. Save opportunity (no cancel)
3.3. "Then" effect is resolved (Go back to Step 3.1) if there are other "Then" effects)
4. Passive abilities (now triggered) are initiated
5. Responses
6. End of action. Moribund cards leave play
Please criticize, the objective is to have a clear ruling for these effects, hoping it will end up some day in the FAQ.