usability testing - Best order of user research

Context

I'm planning on doing user testing and research to help improve the UI and UX of our portal/website.There are a lot tools to help improve your product. Think of tools like card sorting, user interviews, user tasks, etc.

I’m going to use card sorting, user interviews and some testing with the current version of our portal. A few of these tools can be used without the actual product. For example, you can do a card sorting test with users who have never seen the product before.

Note

This testing will happen before the first release of our portal, so we do not have users. We're playing on asking potential users without prior knowledge of the portal. When I refer to 'users' I mean potential users we've asked to come in and test our portal.

Question

Should you do user interviews and card sorting before or after user testing with the current version of our portal, like completing user tasks?

I can imagine that users might have more context when they know about the product but it might also cloud their opinion when they have knowledge of the product before the actual testing.