Oh my goodness, is that a tough situation. I wouldn't think it cowardly at all to tell half-truths or give a somewhat evasive answer. If there's anything we nonbelievers believe, it's that life is precious and not worth that sort of risk. And it certainly doesn't seem likely that you could fake being Muslim; I would imagine that impersonation, if uncovered, might be most inflammatory and most likely to lead to violence.

This is perhaps an ignorant suggestion, as I know almost nothing about the Middle East, but would claiming to be Baha'i be an option? I have a close friend whose family is Persian and Baha'i (though he himself is secular) and from our limited discussions on the topic it seems that the Baha'i faith is a bit like the Middle Eastern version of Unitarian Universalism. It seems fundamentally monotheistic, but considers several big religious icons (Abraham, Jesus, Mohammed, Buddha, etc.) as divine messengers.

Is Baha'i another irrational set of supernatural beliefs? Probably. But it's possibly also a way to avoid trouble...

Good luck, and be safe!

Dave