What is the accusative in Latin?
The accusative case is the case for the direct object of transitive verbs, the internal object of any verb (but frequently with intransitive verbs), for expressions indicating the extent of space or the duration of time, and for the object of certain prepositions.
Does Audire take the dative?
By a strange coincidence, though, there are cases where audire can take the dative, though (as the referenced L&S entry makes clear) these aren't common. Based on the examples supplied in L&S, it appears that this dative object is only used when audire means "obey" or "pay heed to" (not simply: "hear").
Does pro take the ablative?
The entry for pro in Lewis & Short mentions at II that the preposition pro comes with the ablative but remarks that accusative is possible in late Latin.