help me with english "buff" "caper" "flight from the Rock"?

[Steve Kim]

here's link to the article I've just read
http://www.freep.com/article/20120612/NEWS07/120612008

there's some points at which I need your help

Part1
For 20th century crime buffs, few capers match the intrigue and ingenuity of the "Escape from Alcatraz," the 1962 prison break three inmates pulled off with stolen spoons, dummy heads and a raincoat raft.
Q1) In this case, what does "buff" mean?
Q2) In this case, what does "caper" mean?
Q3) In this case "raincoat raft" means "boat made of raincoat" right?

Part2
For Marie Widner and Mearl Taylor, the fabled flight from the Rock is all about family.
Q4) In this case, "the fabled flight from the Rock" means "the most talked-about-escape from the Rock(ALCATRAZ ISLAND)" right????
Q5) If so, "the fabled flight from the Rock is all about family" means they escaped from the jail (to meet their family to support their family to provide for their family)"??? right??
as far as I know, If some book is all about something it means it has it as a main theme (contains it). so in the case above, it means the main motivation for their getaway(main factor to their getaway) is their family.
so I've come up with some examples,below.
ex1) marriage is all about compromise
ex2) living is all about happiness (I say this to mean Happiness is the most important part of life)
let me know my examples make sense or not
Q6) Which one is more correct (more acceptable, more used) between "motivation is FROM their family" "motivation is their family"???

[vicecaptain]

Let me go through the article and come back...