1. per person
2. no, the limits cannot be pooled between categories
3. they're French, so strictness varies with how American you look or if they have some other reason to profile you

I checked out LAX duty-free prices last week, and went to Trader Joe instead; everything was cheaper at TJ than the duty free price for the same item, and some things were less than half the duty-free price. I think Florida has TJ and similar pricing, so packing it in your luggage might be more cost-effective, fwiw. Unfortunately LAX duty free is priced for the Japanese and European market (which has high alcohol taxes); cigarettes are cheap, though (but not wine or liquor).