How should I setup GitHub approvals for the IT or Editors for merges?

A key point to realize with GitHub approvals is that you cannot approve your own pull request, so the person who creates a pull request will not be able to vote to approve it. This means you need to be careful in setting the number of people required to approve the merge to work for the group.

The simplest way to handle this is by assuming that the creation of the pull request is an implicit approval (since it would seem logical to assume that the person who creates the pull request approves of it). What this means in practice is that when setting the number of approvals needed to merge, it should be set to one less than needed. For example, if the IT requires 4 approvals (out of say 6 members) to pass the change, the restrictions on the branch for approvals should be set to 3, with the creator of the pull request being considered the 4th approval.