Sounds good! If I could buy Columbus I'd brew it. Ive never used pilsner but I think you'll be fine with just the 60 minute boil, I think malt today is good enough that the old 90 minute DMS boil for pilsner is perhaps outdated. Kind of depends on how vigorous the boil is etc but I wouldn't worry.
Dry hop with Colombus, why not! Another ounce or Id say. Or split the batch and dry hop half to compare.
As to the all wheat...you don't mean ALL wheat and no other malts do you? cause if you do then you might need to look up some recipes, wheat doesn't have enough diastatic power to convert itself so it's generally mixed 50-50 with pilsner +/- other minor additions.
That recipe looks good I have to say, it makes me want to fire up an evening brew session, too bad all my fermenters are full until I can manage to bottle this weekend.