Hi, I am not an experienced cat owner, but have gained a lot of information since joining purrs...
First of all, I am so sorry to hear about your loss, it must have been heart breaking
I got two kittens together, my first ever cats, and have had no trouble at all. They do fight to practice and maintain their status in the household, and still do even tho they are both neutered. Sorry to say I don't think that will calm Sugar down!
I DID do the blow in the face thing, but only when they went behind the tv or on kitchen benches where I didn't want them to go and it did work. However, I wouldn't do it to stop their natural instincts!
The other thing you say about the scratches on you - please don't use your hands as toys. Kittens will play with anything tho - Dexter didn't like 'normal' cat toys, but loved to try and stop a plastic bottle from spinning around!