Good points.
Can a Christian be a spy for his or her country? If so, a central part of their job description is to deceive.
Or what about a Christian actor? Their job is to pretend to be someone they’re not, to help us suspend our disbelief for a time.
A little trickier for a spy or a war-time situation. Again --- as far as I understand it--- the injustice done in lying, is intentionally deceiving a person about information to which they have a right.
Therefore when the Nazis ask you where Anne Frank is hiding, they have no right to this information and if you give it, you are becoming an accomplice in murder, and they ave no right to ask you to be an accomplice in murder. So it is no injustice to say "I don't know" or "It's quite possible she went to France."
As for the spy: I think the various acts would have to be evaluated on an act-by-act basis. Silence is not lying; neither is an ambiguity which the person misunderstands (as you hoped they would.)
For instance, you, a spy, travel about dressed in a Franciscan brown habit. You reasonably expect that other people will think you *are* a Franciscan, but you didn't actually tell them that, and you are under no obligation to correct their mistaken assumption.
I don't think this solves all dilemmas, but maybe it clarifies a bit??