Okay, so to preface this, I'm a Level 50 Pally and only a level 23 Marauder, so I probably cannot answer the "please advise on exact skills" questions too accurately.

1. Mantra for any other class except for Monk is kind of a waste of a valuable cross class slot, weighing in at a mere 5% healing boost. You're better off taking Convalescence instead. Awareness is generally not that useful, but it has its use in giant pulls, as it will push your damage down to more consistent levels instead of letting crits scare you or the healers.

2. You don't want to use your cooldowns... on cooldown. Especially not as a Warrior. They're best saved for moments where you know you're about to take big damage or will otherwise lack heals or something. They should always be used one at a time, as stacking them up decreases their overall effectiveness.

3. You aren't geared enough to worry about giant pulls just yet. Take a step back for a moment and reflect on the fact that you're the Tank; the pace setter of the dungeon. Never do a pull that makes you panic; it always leads to death. If your party gets mad at you because you didn't pull the entire section of a dungeon, don't worry about it. You're the one getting mauled so you know better than them what will or will not kill you

When you are ready for the giant pulls, I figure it's probably a good idea to combine Berserk and Unchained with some Overpowers in order to establish good threat and do some decent damage while you're at it. Use Bloodbath at the same time and you'll be restoring more than a little of your initial HP loss. After some good spamming of that, you've probably got the attention of everything, so you can concentrate on building Wrath and making sure that Inner Beast is up as much as possible. Your other cooldowns should probably be used one at a time from moderately effective(Foresight), to most effective(Vengeance), to the ones you use only if you have no other choice(Awareness, Convalescence).

4. When you want to wreck stuff, you'll want to combine Berserk, Unchained, Internal Release, and keep five stacks of Wrath handy. Get Storm's Eye on the enemy beforehand if you can and you're golden. From there, you probably want to do at least one Butcher's Block combo just to take advantage of the burst in Threat and then do whatever combo hurts the most.

At least, that's the way I see Warriors murdering stuff. Could be wrong though.

5. If you're the off tank, you seem to have the right idea. Keep Defiance off, and there's no reason not to keep both Storms up on the enemy. I'm personally not sure if that's the best option for pure damage, but it's the most helpful option for the raid as a whole, so make of it what you will.

6. Hm, I didn't know there was a Skill Speed threshold for getting two threat combos in during the duration of one Storm. It's probably not the end of the world if you let it fall off for half a second once in a while. Just watch your threat carefully if you're spending a lot of time keeping one or both of them up; a lack of pure threat combos might equal loss of aggro eventually.

7. And there's the bits about Warrior I really don't know at all. Sorry.