I think you'll get good green onions. I'm not sure if you'll get medium heads or small ones as it already is so late and the day length that triggers them to bulb is here already at our house for the Texas Supersweets, as mine already are slightly larger than golf balls. Candy may have a better chance of giving you bulbs of some sort since it is an intermediate daylength variety and starts bulbing up a little later.

You never know what will happen, though, until you try it. At least onions that are planted now won't be dealing with cold weather so they might grow really, really quickly. I've never planted onions later than earliest March.