Instead of using .myClass {}, for:
Wiki, use .p-navEl-link[data-nav-id=vw] {}
Feeds, use .p-navEl-link[data-nav-id=vw_feeds] {}
You may also wish to request for XenForo devs to allow setting extra attributes on Callback type navigation, or to automatically set a unique class for each navigation entry so you don't have to.