The ICJ is part of the UN as one of its 6 principal organs. It does not have the power to issue individual arrest warrants as it only has jurisdiction over states. As you correctly stated the ICC which is not part of the UN issues arrest warrants

It’s unlikely as ICANN has said that it will retire the domain if io is removed from ISO 3166-1 https://www.icann.org/en/blogs/details/the-chagos-archipelago-and-the-io-domain-14-11-2024-en

No it would be the first. .su is still considered a CCTLD http://www.iana.org/domains/root/db/su.html

That would make it the only 2 letter non country code top level domain. And could also cause issues if another country is later assigned io as it’s 2 letter country code by ISO

Tim Eicke, the UK judge at the ECtHR. He gave a talk at my university and I briefly spoke to him afterwards