Looks like everyone has most of your concerns covered (free-feeding, checking out Reaper's list of quality kibbles, having a schedule so she'll know what to expect, etc...), so I'll just add one thing. You mentioned how she'll huff when something touches her back when she's out.
The same can be true for mine depending on where and when her back is touched. If I just start trying to pet her back anywhere, she shows her displeasure by huffing at me. But, if I start petting her toward her tail end, she's fine. Over time, I can pet higher and higher until I reach her head (the top of her head is a don't touch me or I'll huff at you zone ~95% of the time) - it just takes a few minutes to keep her feeling calm. It's still early for you and your new hedgie... you'll come to learn where she's okay and not okay with being touched. For now though, just go with the most "okay" spots... and that might be lower back rather than mid- or upper region. Or even just holding her without any petting, like Kalandra mentioned.
The same can be true for mine depending on where and when her back is touched. If I just start trying to pet her back anywhere, she shows her displeasure by huffing at me. But, if I start petting her toward her tail end, she's fine. Over time, I can pet higher and higher until I reach her head (the top of her head is a don't touch me or I'll huff at you zone ~95% of the time) - it just takes a few minutes to keep her feeling calm. It's still early for you and your new hedgie... you'll come to learn where she's okay and not okay with being touched. For now though, just go with the most "okay" spots... and that might be lower back rather than mid- or upper region. Or even just holding her without any petting, like Kalandra mentioned.