There are muslims claiming to be Christian to gain refugee status and there are plenty of leftist “Christian” charities enabling them to be here.
Get some actual Middle East Christians (vetted through such people as known conservative Catholic and evangelical luminaries in the West) and let them in turn be part of a vetting squad.
Muslims are allowed to lie by their faith, but their hearts won’t be in the lie and they will be pretty easy to trip up by a knowledgeable questioner.
Quite simple to vet them. Force them to attend a pork roast and eat the pork, place hand on the Bible and take an oath, and sign document refuting Islam. Take lots of photos of each of these events. Once thy go postal, post all the photos and the documents. They will be cleansed by their own.