At least 10 - the size of a minyan.
No, the men in the concentration camp did not remember to say the Kaddish for Akiba Drumer in the book Night by Elie Wiesel. They were consumed by their own struggle for survival and had become desensitized to the suffering of others.
You can say Kaddish for anyone you know that has died. However, if your parents are both alive, you should seek their permission.
The tradition is to say Kaddish for 11 months after the death, and then for life at Yizkor services (on Yom Kippur plus 3 times a year, once for each pilgrimage festival). You need a minyan to say Kaddish, so it's usually during the 3 daily services, but you can say the kaddish after study if you are with are a minyan worth of Jews who have studied Torah (broadly interpreted).
yes
Kaddish is said at the end (and at several points in the middle) of every prayer service. Kaddish is also often recited at the end of a Torah class or a Siyum--the completion of one of the books of the Torah. Often a bar mitzvah boy will "make" a siyum and kaddish will be recited. But just to say kaddish at the party, no.
Technically, an individual recites the Mourner's Kaddish during the worship service only during a limited number of days or months following the death of a parent, spouse, sibling or child, and then annually on the date of that relative's death. It also happens that one recites the Mourner's Kaddish if requested to do so on behalf of an individual who is required to recite it, but who knows that he will be unable to attend the service. Though understandable, it would be considered odd by many if the Mourner's Kaddish were recited by a person of whom it was neither required nor requested. But he certainly could not be prevented from reciting the prayer, which contains only praise of the Master of the Universe, and makes no mention of death.
Yes, it can be done, but if you can't travel, you can say Kaddish in your synagogue.
As long as they want.Jewish answer:Eleven months.
he thought it was wrong
Akida Drumer asked the others to say Kaddish for him three days after he left, and no they didn't say it; they forgot to say it.
Kaddish is a Jewish mourning ritual, so yes, a daughter would be expected to mourn the death of her mother but I don't believe it's obligatory.
No. There's actually no compelling reason to have a baal t'filah at all, if fewer than a minyan have given up waiting and just decided to go ahead and daven. But if ... early in the morning, for example ... you think a minyan is likely to arrive, and a baal t'filah began the brochos, if there's still no minyan when he reaches a kaddish, the mourners don't say it, and in any case when a kaddish is reached without a minyan, it's not said.