e), we currently have twin goals: the advancement of heritage and promotion of education for all. If we drop one, it's singular; as it is, I think it reads better to regard them as plural. The Charity Commission guidance on permissible purposes is at [http://www.charity-commission.gov.uk/spr/ca2006prov.asp#0]; the key line here is "the advancement of the arts, culture, heritage or science". I like mentioning heritage, but it does raise the question of why we don't also mention the advancement of culture.
Well, we're aiding the advancement of all four of those by supporting the free distribution of knowledge. From the point of view of science, distributing knowledge is of fundamental importance to the advancement of science - up there with doing experimental tests (if you do a test but don't spread the resulting knowledge around to everyone, then it's useless). Heritage is obvious in the digital preservation of documents and information, as well as photographic/ audio/video records. Arts is more tricky, but I would have thought that communication is also as fundamentally important there as it is in science. Finally, one could argue that Wikimedia is turning into a culture in its own right - it's certainly playing a role in the cultural changes coming about as a result of the internet.
I don't want to argue that our goals consist of all of the buzz- words; perhaps something more simple like stating that the fundamental objective is "The charity's objective is the collection and distribution of all forms of knowledge to all under a free license or in the public domain, by means ...[etc]"?
Mike