Hello there @WillHei - thank you for your question & welcome to the community!
We actually have a beta version of Local available that will make this process much simpler and straightforward such that you can connect your WP Engine account and create a new install in WP Engine, all from Local.
However, if you don’t want to wait for that release, I would suggest you follow these steps:
Create a new install in WP Engine
Push this local site to the new WP Engine install via Local Connect.
There should not be an issue with your credentials - but do you have a specific concern?