[Varyon]

Unarmed Parry lets you use a specific weapon skill for Parry even when unarmed, so Enhanced Parry to that skill should enhance it as well. I'm not certain how Unarmed Parry (Broadsword) and Enhanced Parry (Unarmed) are supposed to interact, but my assumption is the intent was roughly "not at all," as someone with Unarmed Parry (Broadsword) has that Perk so that his/her high Broadsword skill allows for a better unarmed Parry than using an unarmed skill, at which point there's no good reason to invest in Enhanced Parry (Unarmed).