#2 - This (grappling, unarmed melee vs armed melee) isn't covered in the rules somewhere?
Some game (that I can't recall off hand, no doubt others as well) allowed parrying without a weapon (barehanded parry basically). The penalty being you took damage from the attack whether you were successful or not (iirc, though I don't recall just what advantages it gave for success).
Not only is that realistic (knife fighters will teach you that a cut to the hand or forearm is preferable to one to the body) but it can often take your opponent by surprise (they don't expect an unarmed person to close with them, let alone attack their knife). And once you have stepped inside his reach you switch to grappling and neutralize the knife as a weapon. Theoretically of course. Practically it takes a lot of skill, practice, nerves, and/or a little luck.
I would suggest parrying without a weapon be limited to very short weapons (knife, dagger, blade, club, for example). Attempting to parry heavier, longer, generally two-handed weapons (swords and such) will leave you with one less arm... each time. "Tis only a flesh wound you coward! Come back here! I'll kick that sword out of your hand!" (lop and there goes a leg... ). I might also go with something like:
Unarmed Parry (average task, Melee - Unarmed )
Failure = Take the maximum damage possible for the attack as if it were successful. Combat continues normally but the surprise element is lost, further unarmed parry attempts are at -2.
Marginal Success = Take the minimum damage possible for the attack as if it were successful. Combat continues normally but the surprise element is lost, further unarmed parry attempts are at -2.
Average Success = Take the minimum damage possible for the attack as if it were successful and switch to grappling/wrestling (opposed checks perhaps for weapon control or breaking the hold).
Exceptional Success = Take no damage from the attack and disarm the opponent (keeping the weapon an option perhaps, breaking/dislocating the opponents arm as another).
If someone really insists on parrying larger weapons, let them, with a penalty of -4
