I think you are giving bad advice here. Which Ivies do not meet full need?
I guess no school meets full need depending on your definition. But even Brown which is probably the least generous (and probably the only one D21 will apply to, sigh) meets their definition of full need. The least generous Ivy is still probably middle of the pack or better for “full need met” schools.
You do need to check out what that means. But if you have relatively vanilla circumstances, the NPC’s are pretty accurate. It looks like from another of your posts you are getting hampered by a ex-spouse with a high earning spouse. The NPC’s generally will say that they are not accurate for divorced parents or business owners. If you have either of those circumstances, or a high home equity, you need to dig a bit deeper.
For low income a kid who doesn’t have to worry about self employment or divorced parents with extra incomes, these schools are cheaper than a state school with free tuition.
If we are talking a kid with parental income north of $100,000, which I realize depending on where you live isn’t eactly wealthy, it gets a bit more complicated. But the OP said he was low income. I don’t think even in a wealthy part of the country someone with a 6 figure income would classify themselves as low income.