You sure you want to use Columbus in a wheat beer? I love me some Columbus, but the dankness doesn't seem to fit what I'd look for in a wheat beer.
Oh good. I would think they will be greatly overpowered by the citra. And a 5 minute addition should be more aroma than flavor.
I'm a big fan of Boulevard's 80-acre hoppy wheat. On their website it states that they use Bravo, Zeus, Summit, Cascade, Nelson Sauvin. 20 IBU's. Nelson would be a great hop to try, if you could get your hands on it.