They're not doomed; it's just gonna take time to harden them off. Start them in a shaded location (full shade to dappled sunlight, maybe North side of house... if you have no shade start them with only an hour of early morning or evening sun). Avoid the high UV hours for now, because they can sunburn really easily at this point. Give them a week before adding more time in the morning or evening sun. Keep adding more time and stronger sun as they adjust. Also protect them from strong wind. I have an easier time hardening off the trees that grew under fluorescents, because the natural light is quite weak in New England during the winter. You just need to go slow either way... and use the light and shade you have to your best advantage. At worst, if you move too fast they sunburn and lose leaves. That'll set them back, but if you are in a short season area of New York the gains could still well outweigh that temporary setback. With a little practice winter growing can give young cuttings a big advantage in cold climates. I don't think I would attempt a tree of the size you mentioned without strong fluorescent lighting though, as it could get leggy otherwise. Best of luck!
Edit: ahhhh Matt beat me to it. Hehe.