toilet seats don't leak water. Have you checked your tank to bowl gasket? Did you screw your flange down to the floor? You should not have any rocking. What is your drain pipe made of? If it's before plastic you may have lead piping that needs replaced. You can pull up the toilet and pour water in the drain and see what happens. That will help separate the drain from toilet as the cause.
I don't like the no seep bowl waxes because I feel the insert allows paper to hang up on occasion causing the next use to be unsuccessful. Most plumbers are not agreeing with me and feel they use the inserts without problems. When I'm the third plumber on a job that hasn't been solved I feel I have solved it by replaced the wax with a regular one. However they may have just called the fourth plumber.