css 1.0? 2.1 is probably a much more realistic assumption. I doubt anyone is using a browser that outdated. Also seeing as how this is a progressive enhancement utilizing css3 why would you attempt css1.0

furthermore the codebase is not consistant in this usage anyway

That code is just in their in that manner because the original author preferred to code in that manner as a preference.

Also as you may no HTMl selectors require more load time to traverse than classes as their are more of them used per page.

Anyways as far as the specificity goes you still do not need 

ul.profile-icons li.email-icon = 2x dom traverses

.email-icon is plenty = 1 dom traverse