Update:

I have spoken with various individuals and discovered
1)it is possible to get the 3-yrs age difference limitation in the same classroom waived. 2)the dual enrollment standards are set by the Universities. There are two good university options that we can choose from that are not limited by age.
3)In certain subjects, there are required state proficiency tests. I was told to keep good records reflecting that she is covering everything in the state standards and then have her take the state proficiency test for that subject to get credit.

Right now, I am feeling hopeful and very glad that I am asking these questions and preparing now.