I've tried 3 times and only one of both adepts survived and entered the Allied outpost.
Hint hint: Pillboxes fire at civilian vehicles too. (actually, that's the hint Speeder gave me when I myself was stuck -.-)
I know, that's how I sent my adepts into the base.
Sometimes the name of the mission tells a lot about the mission itself, so it is worth to "decode" the hidden hints.
The sniper on the left side can be taken down by capturing a civilian (not car) and using that unit as a human shield. The trick in this that the Trooper must be right behind that civilian to be able to capture the sniper. If you do correctly the sniper will shoot down the civilian first and his sluggish reload speed will allow you to capture him. Needs a bit of practice though.
The right one is a bit easier due to the presence of sandbags.
Though I've never completed this one, because I really hate this, but I know the first 50% of the way.
I also noticed that (the name of the mission) and that's how I eliminate the left sniper.
I'm depicting how I complete the first objective.
I first dealt with the right sniper by having one of both adepts control one of the G.Is guarding the entry and he will be killed by the sniper. I then ordered the other adept to control the sniper and he got killed by the pillboxes around him.I then went to the left path, controlled 2 G.Is to take down the 2 patrolling G.Is and a dog and used them as the HUMAN SHIELD to draw sniper's fire. My adepts followed after them, controlled the sniper to get him killed and then moved back to the village.
That's how I complete the first objective.
The problem is how I can enter the base safely.
I controlled 2 civilian vehicles to go with adepts.
I first ordered my adepts to draw the attention of the turrets and then ordered both the civilian vehicles to draw the pillbox's fire. My adepts of course moved after them.
The pillbox always killed both civilian vehicles as well as one of my adepts.
With only one adept in hand, it seems that there's not much I can do as I can't let any of the spies get killed unless I like hearing "critical unit lost", LOL.
I'm gonna try more to finish this stage.