From the IRS FAQ in your post:
"Taxpayers likely won't qualify for an Economic Impact Payment if any of the following apply:
...You can be claimed as a dependent on someone else’s return. For example, this would include a child, student or older dependent who can be claimed on a parent’s return."
Do you see where it says “are claimed” ? No? Neither do I. I just see “can be claimed.” If Sally is in college, has she studied enough English to know the difference between “can be” and “are” ? Well, OK, at some colleges these days that might not be covered until grad school. Is Sally an adult? How much did she pay you to prepare her original return, and her amended return? Do you think it’s a good idea to work with her parents to help her circumvent the rules? Are they paying you enough, to ease your conscience about that?