Any magic attributed to such objects is the stuff of legends - not really confirmed. Such objects may actually have no magical powers. I wouldn't make deductions about the nature of magic from such unconfirmed stories, and I don't think God would. If He does, there is really no way to find out, not that I know of.
There is no proof that the Holy Grail even exists BTW: The below link is for your money, not you mind. My advice, don't follow it.
Well that depends on what you think the holy Grail is. Some believe it is the cup Jesus drank from (which means it was used by Jesus at the Last Supper) and some believe it is the Virgin Mary herself.
Because he was arrested as well.
No, but he did apparently catch a glimpse of the Grail and fainted. Likely because of his affair with Queen Guinevere he was unable to attain the Grail, like his son Galahad did.
There are many false interpretations of the Holy Grail. For example as Mary Magdalene and the bloodline of Christ. But the real Holy Grail is a spiritual path which was described in the Arthurian romances. For an up to date scientific appraisal of the Grail story see http://www.theholygrail.org.uk.
He did not die after drinking from the Holy Grail because his son made a "wise choice" when he picked it.
No I believe it was, from what i read, it was Sir Richard's last squire, Tristan
Trevor Ravenscroft has written: 'The cup ofdestiny' -- subject(s): Occult sciences, Grail 'The spearof destiny' -- subject(s): Holy Lance, Occultism
This is because it can repair humans and possibly extend the amount of years a person lives, just like holy grail.
The Holy Grail is different from real cups, vessels, dishes, and plates, is that the Holy Grail is a work of fiction, first appearing in the 11th and 12th centuries in medieval legends; the other things that you mention are real utensils used by men.
The Unholy Grail was created in 1962.
The Children of the Grail was created in 1996.