Abilities(Mostly Passives) Damage & Stacking

[teozamait]

I've got a couple of questions related to how some abilities actually work, most of them are related to one another:
1. Do bonus damage abilities (examples:Bash, Maul, Critical Strike, the toggleable Destroyer's area attack ability) ignore armor type or value and stack (by stacking I mean one Critical Strike ability with 10% and one Critical Strike ability with 20% crit chance give the unit 30% crit chance?) if not added by items? (obviusly the stack part is only for passive abilities)
2. Do passive resistance abilities (examples:Evasion, Mountain Giant's anti-magick and anti-damage armors, Blessing of Elune, Drunken Brawler) stack if not added by items?
3. Does Barrage stack? (say one barrage activates every 5 seconds and the other every ten) Also, can Barrage trigger unit animations (for example be used to play a units alternate attack animation)?
4.Do passive area of effect abilities (examples:Tauren passive ability forgot the name, Orb of Fire damage bonus, Cleave-- I know this one does ignore armor) stack and to they ignore armor type or value?
5. Last but not least, how do the abilities from points 1,3,4 interract (if they even do) with the Mountain Giant's reduce attack damage armor passive ability-thingi?

 

[Death Adder]

2. Any passive that isn't orb effect stack, i think.

I think autocast attack modifiers count as orb effect when used, besides searing arrow.

4. Tauren passive deals damage around the user, cleave deals %dmg of attacker in aoe around the target (ignoring armor value but not armor type) splash depends on the 2nd attack of the unit and does not ignore armor since it's just a normal attack with splash.

5. Reduced attack damage taken.

 

[teozamait]

Thanks. Still, can anyone else clarify the other stuff?