Bunions aren't caused by shoes. You need a pre-existing mechanical defect in your feet. Bad shoes just speed up the process if you already have such a defect. You guys all know I don't wear pointy toes and high heels, and I have worn sneakers most of my life, up until I was about 19 or 20. Yet I still have bunions on both feet (I got them removed on one though), because I overpronate a lot. I guess if you wear 4" heels and pointy toes every day, even with perfect feet, it can cause some disfigurement...but most women I know of alternate between flats, low heels, high heels, and different toe shapes. Anyway, I would not worry about bunions, especially if there is enough room in the toe box.
I agree with Ana that stretching is the way to go. Nordies can probably even stretch them for you, and yes, it can be done in just one spot.