How much did your D receive from the grandparent owned 529 each year?
Does she qualify for Auto Zero EFC as well?
If you are looking at CSS profile schools and institutional need based aid, remember that aid will decrease and EFC increase when the older sibling is no longer attending college at the same time.
It looks like you will have two in college for 2020/21, then one for 2021/22 and three for 2022/23 and 2023/24, then two for 2024/25 and three for 2025/26, then one for the remaining three years?
That combined with the changing income can change EFC drastically, which will impact federal aid and institutional aid.
You might want to run some net price calculators with different income and students in college scenarios to see if the schools would be affordable for all four years and whether any aid changes would be able to be made up by the college savings provided by grandparents, student loan and summer earnings.
Auto zero EFC has a pretty low income limit of $26,000 I think (2020/21 EFC formula).
I don’t think it matters for that what the family size is.