1&2) Can't repeal Supreme Court decisions. Either new case leads the court to overturn previous decisions, or it requires a Constitutional amendment. Neither's likely 3) More complicated than you assume 4) Yes 5) Yes 6) Already might be the case 7) You don't actually want thishttps://twitter.com/keithboykin/status/937494552100966400 …
That's not how it works. And I'm not sure you'd want international courts superseding America's Supreme Court. Maybe on some issues, but not on others.