We are building app to create product videos and uploading the same in shopify.
What is the copyright policy with those uploaded videos ?
I am not a lawyer, this is not a question you ask on a forum this is a question you confirm and clear with an actual lawyer as any "answers" here do not protect you.
Copyright is the same as everywhere else where the berne convention and other intellectual property laws apply and under whatever contracts,licensing,terms or local laws apply.
Anything under a developer preview is to be assumed to have no public support.
if you have to enable a developer preview to use a feature then it's a developer preview, Assume no support.
To see if a feature is accessible "publicly" outside of a developer preview simply test for the endpoints on a regular store remembering version headers.