How to import issues from BitBucket to GitHub

No that feature is not available in Github public repo , for that you need to purchase the private repository

Not the way you're thinking of at least in GitHub.

What you could try is have two separate repos with their own access list using Organizations and Teams.

When you create teams in GitHub you can also restrict access to certain repositories per team.

So you can set up the following:

• dev-repo - Only add and allow access to developers
• audit-repo - Only add and allow access to code auditors

Then, when dev-repo has new commits, pull down the changes to your local and push them back up to audit-repo.

Auditors can then leave comments and issues on their version of the repository under audit-repo and you can then relay any issues you think dev-repo should know about without either developer or auditor team seeing each other via these private repos.