What purpose do the dugouts serve if they are part of the scenario set up but do not award points?
Hidden deployment and/or slow down defenders (being in a dugout was rarely a good thing when there was a raid).
Do they provide any benefit for the player controlling them?
Can't be attacked or identified. Again, they are usually not included in a scenario to help the defenders. Usually they want out asap.
Does line of site for range have to be in a straight line? Or can an attacking unit with a range of 4 located in hex 0403 attack a nuit in hex 0206?
On mobile, no map here, so can not comment on specific hexes, but there is no LOS in thr game, you just count hexes any path you want.
Attacking a target that is in a trench gets a +1 drm when the attacking unit is outside the trench to make it more difficult?
Does the attacking unit add +1 also if both the target and attacker or in connected trenches but more than one space away? IE: one hex between instead of adjacent?
+1 if not adjacent
Which pieces would you use for New Zealand and Australians in the expansion?
British. Think there is a note of that?
You cannot move and attack with the same unit in a single turn correct?
Only with the help of a leader.