First, lets begin by identifying two methods of warding.
(TYPE 1)Warding vs the individual:
Base 15 Corpus
Base 2 Animal
This prevents the person from "attacking" you, and as such will deflect all blows/attacks by that individual, but wont' stop thrown weapons for example (should a bear ever throw tree, a sword or a dagger at you, it would not prevent that either. It would prevent a thrown person or bear however).
(TYPE 2)Warding vs the type of weapon:
Terram
Herbam
Warding vs stone/metal/dirt or wooden weaponry depending on the spell.
a) Type 1 & 2 wards protect vs all attacks from targets that do not have magic resistance.
b) Type 1 wards will NOT protect vs an attack by an individual that has magic resistance unless they penetrate. (Natural attacks of a Magus, whether it be brawl or a Bjorner in Heartbeast form)
c) Type 2 wards will protect against attacks of that sort from any individual with magic resistance, UNLESS, the offending weapon also have magic resistance - this is extremely rare but is true in the case of Talismans. (E.g. A ward to protect vs Metal Weapon, will work against all weapons ... except that flambeau weilding his Great Sword talisman, because that is covered by his Parma, unless of course, the ward was cast with enough success to penetrate).
d) Talismans and weapons that are magical in nature, are stopped by Parma Magica, unless they can penetrate that.
First I would not agree with the classification. Wards seem to be split into T: Circle or not T: Circle, and there are wards that provide Soak (partial warding) if the source of damage is strong enough.
I'm not sure I would agree with the thrown weapon part of your type 1 description. I would still consider that acting across the ward. However, I would allow chopping down a tree and having the tree fall across the ward because to me the action on the tree would be separate from the action of it falling. However, if you push the tree to make sure it falls the right way, then it would be warded because the tree falling is part of the person's action.
Item (d) is very questionable. In canon a beast in its normal state and with Might is not resisted by Parma Magica. Therefore simply being magical in nature is insufficient to trigger Parma Magica's resistance. And so how is this different for a sword with Might in its normal state? At what point this ends is questionable.
I think the OP meant T:Ind wards. Under that assumption, a) b) and c) all seem correct. In fact, if a target is warded against corpus, you can even swing a sword against it, not just throw a dagger. Hit it while wearing gauntlets? Sure. Hit it while wearing gloves of the sheerest silk? Hmmm, ok, that's pushing it.
d) is debatable. Obviously, if the magic item has some magic effect active on it, it gets stopped by any unpenetrated Parma. But an "inactive" item? It really all depends on how you interpret the fact that "enchanted items are created through a type of ritual magic". I'd have them stopped by any unpenetrated Parma, i.e. I'd agree with the OP. But it's far from clear cut.
I agree with Ezzelino: a), b) and c) are correct, d) is debatable, it's clearly true in the case of objects or weapons created by magic or under the effect of an active magical effect, but whether it is true of Talismans/enchanted items that are not active is debatable. They are not listed among the examples given on the functioning of Magic Resistance, and there are arguments for or against making them resisted. In the end, the best thing to do is to make it a House Rule, one way or the other, and work with that: don't let players invest major time in making one only to find that their expectations on the subject were wrong.
Oh, and a minor correction: magic weapons are stopped by Magic Resistance, not specifically Parma Magica. So even if a magus is caught without his Parma Magica, he still has Magic Resistance from his Forms and they will still stop a magic weapon, or a magically thrown normal weapon.