A348: Spellcasting ability is just that, "Spellcasting ability", as far as feats are concerned. Spell level available and type (Divine/Arcane) are often referenced. Casting class or list is also referenced. They are not Ex, Su or SLA's; they are spells. If they are not referenced, nor their parent rules referenced (they are magical, thus affected by the rules of magic), then they are not affected.
Edit: I'd have to say that this is grayer than I thought, but that Spells are class abilities, although some creatures get them without character classes.