Things to watch out for?

[ElectricChicken]

Guy and Gals,
A few questions please.
1) Flipping a kayak would be the most dangerous thing that could happen to a person I would suppose. What is the most common mistake made when this does happen? i.e. turning around toward the back of the boat, etc. Every vessel has its inherant weaknesses and I would like to know what my sister needs to be most mindful of in her new kayak.
2) Life vest - What is the best thing to use that is comfortable yet reasonably priced.
3) Does everyone where their PDF while fishing?
4) Would a throw cushion be a wise choice?
5) Rods & Reels - I see mostly spinning tackle in most kayaks. Is there a good reason for that? I would think it would be easier to cast and more distance with less movement and effort?
6) Ice chest for fish - I just watched Raginjrob's video and saw that he had a collapsible ice chest. Is that a better choice than a hard side ice chest?
7) Plugging holes in the bottom - My sister went out on her first trip and her feet stayed wet because the drain holes kept some water in the boat. Should she plug these?
I appreciate any and all input. Thanks. EC