Yes, a ward would break a Law. Don't read this if you haven't read Changes yet, but Harry had to disable his wards for when the FBI broke in, otherwise it might've killed them. Which is bad.
You can tie a Ward to prevent certain things, if you have something of that kind of thing. Get some Red Court ichor (not sure if it is actually blood) and you could make a ward that stops them alone. I suggest going on a monster killing spree, gathering samples for your wards. Get some ghoul blood, Red ichor, etc. Tie them all to your ward, so that you don't have to worry about killing someone. Add a nerfed ward as well, that works on humans and whatever you missed in your uber-ward (immobilization could be good).
Don't be so sure. Dresden may not have been thinking, "Oh crap, I'll be a lawbreaker for sure!" so much as, "Oh crap, I don't want some innocent FBI agent just doing his or her job getting flatlined for pulling the wrong straw on the wrong day!"
Harry's also a decent guy. Not every concern he has about someone dying is about his being afraid of losing his head. Sometimes it's because he's a decent guy.
Whether it's actually lawbreaking though? Hard to say. Although I'd argue on intent, here, the fact that the rulebook comments on blowing someone off a building with an airblast is lawbreaking. Then again, I don't think the rulebook said, whether it was commenting on the intent of blowing someone off the wall.
For example... if I kill someone with a fireblast, that's lawbreaking. If I blow someone off a building with an air blast, that's lawbreaking.
But if I set a building on fire, but the fire itself is nonmagical, and THAT ends up killing someone a few minutes down the road, is THAT lawbreaking?
For that matter, a rather aggressive ward designed for defense - if a particularly nasty defense - is that lawbreaking?
I'm torn either way, honestly. Jim Butcher's books don't address it in specific detail, and neither does the rulebook. I'd say, if you set it up knowing that mortals might be coming and triggering them, then yes, it's lawbreaking, but if it was an accidental and unintended side effect, then no... but Morgan might disagree
And frankly, I can see it either way, so I don't aggressively stand by my statement here