To cover a few of your questions, how we do it:
We blow hero right at the start to gain most dps out of the hero, the enrage isnt hard to beat if everyone survives, but shit happends and this will give you a lead.
Pallytanking threat on this fight is amazing so you should start off tanking, pop wings and see how dps cant reach you on omen

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At 3 phase punches (cast every now and then bossmods have an pretty exact timer) we swap tanks, the 2nd tank does a 3 sec countdown in order to get the healers ready. We found this to be the perfect stack rotation with the big bangs.
This will make tank1 get 3 stacks, then tank2 taunts and he will have 2 stacks, sometimes a 3rd right before big bang is casted, and also make Tank1's stacks run out right in time for big bang, so when its over, Tank1 starts tanking again and this rotation goes all the way to the end. Make sure your healers know that Tank1 will always star tanking after a big bang to get buffs and shields up on that one.
Big bang are also on a accurate timer on bossmods and as you know someone has to soak it. We found tanks to be the best since then theres no aggroissues whatso ever, some do it with a shadowpriest (think this is most for 25man tho?).
We have me soaking with Salvation and Divine protection on first and 3rd big bang (Divine Protection will make you survive it alone, but theres no threat issues since those down in the phase realm looses all aggro and less dmg taken isnt bad), and having eather Painsuppression or Guardian spirit, if none of those are available maybe the second tank has some CDs of their own and can take the 2nd Big bang.
Every now and then he will cast cosmic smashes, bossmods have an very accurate timer for this aswell. It will look like a very small fissure you really have to get out of, no need to run across the room, a few steps 5-10yards will get you pretty safe, however the further away the less dmg. Once your 10yards away the dmg isnt really noticable. If you get caught in it youll fly up in the air and will prolly die or cause a wipe.
Stars, they will spawn a bit into the fight, about 30sec or so i think.
Collapsing stars move around everywhere in the room, not sure if they got a preset path or not but they seem to avoid the middle of the room. Tricky thing with these are that they loose health all the time, one or 2 %/sec, a dedicated killer for these stars are required. They dont do anything to ppl close all they do is that when they explode they will do aoe on the whole raid, shadowdmg so auramastery on a holy/retri would help but not crutial. When they die they leave the black holes. Have your Starkiller announce a few sec before one is gonna blow, for healers to prepare. Also make sure healers and dpsers have emeny nameplate on, that way they can see for themselves if a collapsing star is running close to them with low health. Have your Starkiller mark the adds he is killing so that a black hole doesnt spawn ontop of them making them go to phaserealm and be useless for a time.
Constilations flying around isnt much of a deal, they dont have a meele attack from what ive managed to see, and all they do is cast arcane barrange on random ppl every now and then. I usually taunt them off from our raidhealer in order to just get control of them, they will still hit random ppl even if your "tanking" them, i do this for a simple failsafe, since what have happened to us is that the healer with the aggro on them goes into a black hole and closes it before everyone is safely in it, this way he doesnt have to think about it.
Somewhere around the middle of the fight there will prolly be a lot of black holes around, and after tank2 taunts algalon off from you, you can run around closing a few black holes, mainly those close to meele, so they dont accidentally goes down when they are running away from cosmic smash.
Oh ye, and at 20% adds spawn, nothing to worry about just try and pick them from the healers. The black holes also reposition at this point, or more exactly i think they despawn, and then 4 new holes spawn so that noone has to care about killing stars anymore.
Think this covers a lot, but atleast the most essential parts should be in there.