"and didn't show she was taken as a dependent on her parent's 2018. She later amended her 2018 return which showed her as a dependent on her parents return. Parent's filed a 2018 return taking Sally as a dependent. Except for dependency issue"

Except for? I believe you mean, "I intend to do what applies given their reality."

"Or do I wait until Sally's 2019 return is eFiled before advising her to deposit?"

You realize nearly nothing is being processed by the IRS? What good is waiting?

How about:

File what applies. Now they see why they need to pay attention.

Sally keeps the money that came in Sally's name.

Everyone files 2020 taxes correctly, factually, and on time, and the stimulus checks are reconciled as part of 2020 tax filings.