You’re good. It is very typical for SCEA applicants (i.e. HYPS) to also apply EA to some of the public Ivies.
There’s some subtle nuances in how the SCEA, REA and EA rules at various schools interact. The key thing is to always always check the rules for BOTH schools. Just because it is OK for Yale rules does not guarantee that it iwill be OK for Georgia Tech.
As an example (and since your kid might be an engineer), MIT has completely unrestricted EA. So your kid could apply EA to MIT and MIT would also let your kid apply early (regardless of ED/SCEA/REA/EA) to every other college that exists. But that would be a problem for Yale SCEA.