My big tree (Arbequena) has a lot of leaf burn but I don't think it will die from the cold. My small tree (unknown cultivar) has no damage at all but I did cover it on a few of the cold nights.

Getting the trees to survive is one thing, getting a decent crop of olives is another. There are supposedly plenty of European Olives growing up and down the east coast but very few of them produce fruit. Plant Delights gardeners have told me in the past that they have a few off in the research area that get no protection at all and that some of them produce fruit.

They're growing them in Six Mile, SC (high foothills). Not productive yet, but you could certainly contact them and ask how they did in the freezing weather. Might be that they'd have to wait to see once they break dormancy. They grow blueberries primarily. But have a number of other fruit as well.

Here is a link that might be useful: The Happy Berry Farm