Don't worry too much about her taking or not taking treats from you just yet. As long as she's eating and growing, that's just great
Goodness... what a chomper she is!
Right, the quick puff of air usually isn't going to deter the chomping. Mostly, if they're chomping, it's because they're trying to say "HEY! Human, something is WRONG!" and then you respond with the air puff... so... yeah... not too helpful. The trick is figuring out what was "wrong" (according to hedgie) in the first place.
Let's try and be really systematic about it. Possibilities are:
You smell yummy. Really yummy. So good that, as a hedgie, I could eat you. In fact, I will. Chomp! (this could happen if you've been handling food recently)
You smell terrible. Really terrible. Like chemical death. I will kill you before you have a chance to harm me. Chomp! (this could happen if you've been swimming - like pool chlorine or using cleaning products like bleach)
You are scaring the bejeezus out of me. I have no idea what you're going to do next. I will make the first move, then all moves from there on out are perfectly predictable. Chomp!
You are hurting me. I will hurt you. Chomp!
I am hurting. I will hurt you. Chomp!
Right now, things are okay. But I suspect they might change. So I will make the first move. Chomp!
So here's what I'd so... and it sounds like you're doing a lot of these things already... so that's great:
Figure out a schedule a really, really consistent schedule of when it's play/snuggletime. And stick to it as best as you can. Hedgies are creatures of habit. If she can come to expect the start time and end time, she'll be in a better place mentally.
Wash your hands and arms up to your elbows with an unscented soap. Find something you like... that you can keep buying... because you and boyfriend and anyone else who's going to pick her up will use this same soap from now until forever.
Think about your clothes too... the detergent and fabric softener and dryer sheets you've been using - they may be way too strongly scented for a hedgie. If you can do all your laundry with the Free-n-Clear stuff and unscented fabric softener & dryer sheets that would be great. Though, I know that may be asking a lot if you have stuff you really like. But maybe you could run a few sweatshirts for you and boyfriend through a cycle with the scent-free stuff??
Sounds like you have a great environment - a nice quiet place, not bright lights...
She may be more of an adventurer than a snuggler... it will take a bit of time to determine her personality. She might be biting to say: hey, let me go play! You can set up a little area with toys for her during snuggle/playtime. You might try putting out mealies (or other favored treats) in and around her play toys so she's actively "hunting" them instead of attacking you. Just don't hand them to her directly. Do not give her any food with your hands, so she's not associating fingers with food.
I currently have a hedgie who, though typically not a biter, WILL bite if I stick my hand in her hedgiebag with her during snuggle time. I think it's her way of saying "my space!" So, with her, I hold her in her hedgiebag and I keep my hands well on the outside. It's nice to feel her just wiggle around until she's comfy, then settle on down on top of my belly/chest for a good snuggle in her bag. The same might work with your little girl. Though, if she doesn't stay in the hedgiebag, that probably lends credence to the idea that she's an adventurer who needs you to set up a supervised play area rather than a snuggle zone.
In my case, my hedgie won't bite if she's outside her hedgiebag... I think it's kind of like a territory thing with her. Sounds like your little girl will bite if she's outside a hedgiebag
Given that, I'd make use of fleece. Definitely, there's value in holding/touching her directly, but since she's using open skin as a target area at this point, I'd go ahead and cover that up. Put on a nice comfy sweatshirt, grab some fleece, keep your fingers away from the danger zone (ie, her mouth area) and start taking note of the little things she IS okay with. Take note of the things she does not huff at when you do them... however small they may be. Over time, the list will grow... though it does seem slow at times. And you may see some back-sliding from time to time. But it will grow.