How to set a default `kind` and `priority` when creating a ticket in Bitbucket

Right now you can't. Jesper has been talking about adding support for that on the mailing list. Hopefully, know that Atlassian bought them, they will have time to add new features instead of server maintenance.

Adding your friend as an admin:

You can put him into a group and add that group to your account with admin permissions.

See Groups for Providing Access.
Quote from the link:

Groups for Providing Access

When you create a repository, Bitbucket checks to see if the owner's account has any groups with a default permissions (read, write, or admin) assigned. If you do, it adds that group to the new repository with the default permission.

Adding the issues service:

In the meantime they automated adding the issues service for new repositories. You still have to enable the issue tracker itself, though.

See Enabling an Issue Tracker in the Bitbucket docs.
Quote from the link:

How the Issues service supports the issue tracker

If you enabled an issue tracker on your repository after August 2012, Bitbucket adds the Issues service automatically for you when you enable the Issue Tracker. Older repositories with older issue trackers may or may not have this service.