1) When does a unit add their Edge(X) to the final result of the Edge battle?

Rulebook, pg 25:

" The “Edge” keyword is always followed by a value. This value is the number of additional Force icons the card’s controller counts in an edge battle resolved during an engagement in which the card with the “Edge” keyword participates."

From the wording of Egde(X) in the rulebook, it's clear that the unit itself must still be participating in the engagement.

So a Heat of Battle on a Snowspeeder when you have two Snowspeeder Operations in play will eliminate their 2 additional Force Icons.

But what if the unit still participates but their edge (x) condition has been eliminated (or triggered)?

Say I attack with committed Reserve Troopers and have two Security Checkpoint ("Each unit you control that is committed to the Force gains Edge(1)") in play. My opponent plays Echoes of the Force in their Edge Stack and uses it to remove the Trooper 's commitment. Do they add their 2 Force icons to the Edge Stack before the Fate Cards trigger or After?

My reading of the "Egde(X)" rule would be the troopers loose their Egde because the Edge battle only resolves after all Fate cards have been resolved. And logically, you can only add the Force Icons after you have something (i.e. a resolved Edge battle) to add.

2) Can Virago steal the Elite keyword when it is relevant?

" Action : Pay 1 [scum and Villainy] resource to have a target enemy unit lose a keyword until the end of the phase. Then, this unit gains that keyword until the end of the phase."

The Elite keyword is only relevant in the Refresh phase, So stealing an opponent's Elite at the beginning of that phase would be quite useful (either because a double-focused Elite unit cannot remove both focus tokens, or because Virago is double focused). However, since there is no action phase before the actual "remove focus tokens" step, it won't be possible to trigger Virago 's action at the right moment.

3) Buried Outpost and Hoth Scout

Can I sacrifice my Hoth Scout to avoid 1 focus token from being placed on my Buried Outpost (" Forced Reaction: After this enhancement enters play, sacrifice a unit or place 1 focus token on this enhancement. ") , and use that sacrifice to place a Shield (" Action : Sacrifice this unit to place 1 shield on a target unit or objective.")?

1. Edge is always on (or off), but only matters during the last step of edge battles when you count force icons. Only participating units with edge at that point in time will contribute.

2. You have it correct, no way to effectively steal Elite with Virago.

3. Nope. The Hoth Scout doesn't get you a focus token any time it's sacrificed, you only get a shield when it is sacrificed via triggering its Action.

1 The edge battle happens in 4 steps. [Ref. Pages 19-20 in the core rule book]

A. Place edge cards (alternate with your opponent until there are two consecutive passes)

B. Reveal edge stacks (flip the edge stacks) remember there are interrupts that can happen before this (see Reversal of Fate from Jabba's set).

C. Resolve Fate cards (beginning with the lower number resolve fate cards. So if there is a heat that damages a snowspeeder that snowspeeder is now discarded if its damage reaches the units damage capacity.

D. Finish Edge Battle (this is where you count the icons, so if a unit with edge is destroyed via a heat of battle their edge will no longer be counted since they are destroyed and no longer participating).

2. Correct [Ref Page 30 of the core rule book]

Reference the timing structure on page 30 of the rule book there is no action window before the elite ability would trigger during this phase as such stealing elite won't do much because it's effect has already gone off.

3.No. Both actions and reactions must be paid for separately. So the sacrifice for buried outpost would have to be separate from the Hoth scout to place a shield. Also note that each action and reaction must be completed in full before another action can take place. This there is no action window to use the Hoth scouts Action ability until after you have complete the buried output Reaction. At this point if you choose to sacrifice the Hoth Scout, he will no longer be in play to use his ability. If his card was worded. When this unit is sacrificed place 1 shield on a target unit or objective. Then this would combo with Buried Outpost, but not as a separate action