Lock Approvals via project Templates / Remove editing rights from certain Plan Access Levels

We have established processes for Approvals in our organization - both at the project and the task level (example: the end-result of a task needs to be approved by a manager prior to the team member moving on to the next task). Right now the Approvals associated with Projects or Tasks can be edited, removed, re-created by the Owner of a project. We'd like the option to lock that, so that the project leads can't even edit who does the approvals - they must happen. Additionally, they can delete Approvals that have already occurred. We'd like this to be disabled, so that the Approval can sit within the project's history.