I’m not familiar with Jekyl or gatsby. But if my understanding of what you mean by static is correct then yes - nothing external is going to impact the layout/content of the website once it’s live (other than version updates on my end).
I was told a requirement was to have a login system and OAuth was recommended. The purpose of OAuth was to allow only people with an @companyName.com email address access the information on the page. I’ve figured this part using the email domain whitelist rule.
There is also an HTML form in one tab that uses PHP to send the form data to a MySQL database.
Sorry if my answers aren’t what you’re looking for I’m new to this… please do let me know if I haven’t answered them properly.