Well, thanks to that list posted under the first one, and more experimentation, I've FINALLY ascertained what those magic items can do, at least on the CV version- the list was for another version.
Here it is:
WAND- This extends the duration of STUN (and maybe SHIELD) spells, and makes your magic arms and armor- the ones already "in action"- more effective. You are better protected from damage, and your Magic Sword does more damage.
STAFF- Similar to WAND, only more effective. It does NOT extend STUN spell duration. What's more, with Magic Sword+STAFF and sufficient stength, you can physically destroy a Living Statue. This is the only non-spell way of doing so.
PROTECT Spell- This lessens the chance of a monster damaging you, and lessens the amount of damage if it does. Only temporary.
Gauntlet- Protects you from poison needle traps.
SHIELD Spell- For a time (brief) gives you a Magic Shield.
STONE Spell- Just like Paralysis Spell. Only affects monsters visible at time of casting. Not time limit, but wears off if you are killed.
Cross- Adds nothing to defense, but allows sword attacks (including non-magical) to do double damage to undead, which, in this game, are Vampires, Ghouls, and Vampire Bats.
Weakness Trap- This drains your strength down to 1 point. ANY healing item will restore it, but as an interesting quirk, you will have more hit points than you normally would.
Cursed Trap- YAAARGHH! This not only saps half of your hit points, it ruins ALL magic items (except Magic Arrows). Magic Armor does NOT prevent this!
Cursed Sword- Like on the list, it can do several things when you "claim" it: be a real Magic Sword; sap hit points; become a lesser weapon- even a short sword!- or drain your Luck down to 0. The only way to get it back is to grab enough treasure to gain 1 point of Luck, and then use a Luck Stone to bring it up to 9.
Magic Arrows- Arrows that do more damage than normal ones. They are never enhanced by anything (even a STAFF), but they are not affected by cursed traps.