If they two little ones die they only look a week old anyway. you're going to go through a lotttt of plants in your life, hopefully. The big one looks big enough to keep growing. If you can't close the vents, maybe you could put up some type of barrier. A tent is ideal and under $100 on ebay, or you could use a big box... or some other creative thing. It doesn't necessarily have to be enclosed up top, just protect them from the wind.
Wind inside the house... it's like really defiant wind. "Screw you, walls!"