Can we rename RTC Approval tracking - Approval, Verification & Review with custom client specific naming conventions?

If you don't need to change the underlying data name, the easiest way to do this would be to modify the Presentation for the work item in question.  Under the project config > Work Items > Editor Presentations you can pick the display for each work item.  You can edit the section header text here.  Note that these are shared by all default work items, so you will update them for every work item (which may be what you want).  If you only want to do it for one, you'll need to copy the Approvals section, modify the copy, and removal the original section.

See this article: https://jazz.net/library/article/130 and just generally search for "customizing work item presentation RTC"

Good luck!