3rd question 🙂 . When seed generates package for prod/staging stage in the Cleanup step from any development stage, does it load the secrets automatically from the prod/staging stage? If not, how should I make this command (this is what seed runs in the cleanup step)

serverless package --stage staging --package .seed-artifacts

to recognise staging secrets?

Yup, the secrets from the downstream stages are loaded when generating the packages.