Will simple Sugar make my "pseudo-lager" finish drier?

Yes, if you sub some sugar for malt (not add it!) the beer will finish drier to some degree. It might or might not make it more lager like. Corn sugar will not add corn (or any other flavor). Soft water is not necessarily what you want for a pils...it depends on the style of pils. But you certainly don't want a really heavy mineral load, either. You can leave out the carapils in your recipe if you want it crisper, too. The real key to a psuedo lager, though, is the same as to a real lager....ferment it as cool as possible and cold condition it for a couple months once it's done.

Adding simple sugars will help your yeast to achieve higher attenuation, with greater effect if you add the sugar towards the end or after primary fermentation.

However, having said that, I have doubts that extra sugar will mimic lager characteristics. You're trying to get the dry, crisp flavors of a lager, but a really low FG is a different kind of dryness, and the mouthfeel will be thin and the beer will lack in body.

You might try adding a small amount (2-4%) of corn sugar. While corn is out of place in a Pils, it might nudge the flavor towards what you're trying to achieve.

I would also pay a lot of attention to your water - any minerals in the water will add to the aftertaste, so soft water is best for getting the dry finish you want.