To me there are two definitions of equality, but one of them may be something else entirely.
Definition 1 - each member of a society contributes to said society. Each has a role to fulfill. Products and monetary objects are not throwaway, and serve a functional/practical purpose. Each member of said society is interested and invests in the health of their community and the society at large.
Definition 2 - basically the modern Western classification - "we are all equal, because." Irrespective of quality or quantity or usefulness.
The key word in your post - "if".
IF equality (as modern Western society views it) exists, then the answer to your questions above are as follows: none, it can't, nothing, no, and no.
But thankfully, despite society's collective neurosis, equality does not exist. Therefore, knowledge has meaning, money only has what value people assign to it, not everyone is equal (some are more useful than others); but I still don't know 'the answer'......I doubt many do.