Square fitments are nice due to the ability to rotate the tires front to rear, side to side, etc. I think you'll be happy with that setup. It's a popular option, and I really like those tires. I owned a set of them myself maybe a year or two ago. The wheels should be about as flush as you'd want to go without needing to touch your fenders. If you're lowering the car I can't guarantee that you won't experience any rubbing, but with a fairly mild setup like that, I don't think you'll have many issues.
As far as the locks go, I'm not 100% sure on them. We've confirmed RAD Locks to work with our wheels, but the OEM BMW ones may be a bit too large.