Question about skill stacking, armor debuff stacking and cancellations

[Cloudiz]

The debuffs ==
*Break Armor 15mana - 5 sec cd; 12 m range 10 sec debuff
Thorn Wall 30 mana - 11/r sec cd; 10m area, 16 sec target damage / sec
Blinding Shot 25 mana - 7 sec cd; 12m range 5 sec hit debuff
Shattering Scream 20 mana - 5.5 sec cd, 8 m range; -16 dmg; -16 armor
Thorn Root 20 mana - 6.25 sec cd; 10m range, 3 sec root, -30 dodge % debuff \

The Main Question I have is whether *break armor is stackable from you alone, like the warrior's taunt? it has exactly the same cd period and debuff time. (Moogerfooger has replied saying it stacks with other birds)

I shall presume at this point thorn walls and the others listed stack with other birds as well.
The only skill of interest to me would be whether my own Break Armor stacks twice, and *refreshes* its 52 pt armor debuff.

Shattering scream : it seems in my observation if two birds cast shatter scream, and say the other bird does a cruel blast before me, it eats up both of our screams? Is this correct? Does the scream debuff last for 5 seconds according to Physiologic?
Thanks