For Reactions…

…ANY unit within 12" may React, correct? If it is a MOVE reaction, those units that can react, may move anywhere they wish…even if it's into Close Combat with another unit?

…ALL units within 12" of an attacking unit may react? I don't think this is the case, but I would like clarification. For instance, can three Allied units React to a single Axis unit performing an action?

For instance, a unit of Zombies reacts to a move by an Allied unit. May those Zombies make a Move Reaction and move into close combat with ANOTHER unit?

Second…

…For Fire Reacts, the unit may only react to the opposing unit that is attacking, correct? When that happens, the damage is simultaneous. So…the attacking unit performs its attack with all its chosen weapon lines…AND…the reacting unit also gets to attack with all its chosen weapon lines?

Is either of these attacks resolved first? For instance, if an Allied unit attacks an Axis unit, and the Axis unit responds with a Fire Reaction. Both attacks resolve simultaneously. Let's say the Allied attack wipes out the Axis unit. The Axis unit still gets to resolve its attack, because the damage is simultaneous, correct?

MRex21 said:

A unit reacting to the movement from an enemy unit may move within 1" of another enemy unit. Neither unit is "Engaged" in anything, they are just really close.

MRex21 said:

Close Combat is an Attack action, not a game state. A unit within 3" of an enemy unit may choose to attack with ranged weapons or its close combat weapons. Zombies being within 3" of an enemy unit does not stop that unit from shooting the zombies during that units normal Attack.

MRex21 said:

Correct, a unit may only react with an attack to the unit that is attacking it. If the attack they are reacting to is Close Combat then they must react with Close Combat.

Reaction fire occurs simultaneously with the attack that triggers it.