Yeah, it's probably all about the edges and angles of which the wind comes on the surface. These round surfaces sound more aero to me as an aero-layman.
Standing starts are a thing. I tend to span my bike into the turbo trainer occasionally, and I am always surprised to see how much flex is in my (rather cheap) alu frame. Not sure whether I would notice it in the cranks, due to a lack of experience. But I will try it asap.
Chainrings are another story. I always have been fond of the Gebhardt one as a cheap replacement for Zen's. They are thick, rather heavy and pretty solid.