Question
What is the reason for the exact order of the blessings in the Amidah? Why is it that, for example, Slach Lanu is #6 or the blessing for rain is #9 or Modim is #17? Why is it that no other blessings were put in any other position? Was it made this way at random, or for a specific reason?

Question
Elokeinu Vei-Lo-Hei Avoteinu Ya-Aleh V'Yavo is recited on Rosh Chodesh and Festivals. This special section is added in BOTH Birkat HaMazon and 5th Bracha (R'Tzei) in the Amidah. On Shabbat we recite R'Tzei V'Ha-Cha-Li-Tzei-Nu in Birkat HaMazon. Is this section recited within any other prayers?

Question
When a parent passes away, the child says Kaddish for eleven months, not twelve. I know it has something to do with the soul of the departed. Question 1: Does a parent say Kaddish for eleven months for a departed child? It is the custom of some people to say Kaddish for eleven months even if it is not mandated - for example: husband for departed wife, sibling for departed sibling. Question 2: Should someone say Kaddish every time the Mourner's Kaddish can be recited after the twelve months? How does that reflect on the departed person's soul?