Yes, if she provides more than half her own support, even form savings or loans in her own name, she cannot be be your dependent. VA educational benefits are ignored in the support test.
If she is under 24 (on 12-31-24) and unmarried, there's another rule that comes into play regarding eligibility for the refundable portion of the AOC. She doesn't get any of it without most of her support coming from from earned income.
I'm gonna need you to pare down your numbers to answer you questions on the calculations. But, a quick glance says they're OK. Don't be surprised if you have trouble getting TT to come up with that $20 taxable income.
If she only has $1100 of income, there is no tax liability, so there is no non-refundable credit. So, she only gets the $768 refundable portion (40% of $1921), unless she's under 24.
