I've gone through the rulebook without finding any answers so I humbly ask here. Thx for any answers.

Q1 : Does the Savage ability stacks with itself like toughness ( EX : I give Savage 2 to a unit with Savage 1 does it make it Savage 3 )?

Q2 : Does the Savage ability triggers even if the unit is destroyed ( from now on I supposed that yes or else Lizardmen really are the poor children of WI)?

Thx.

Q1 : Yes

Q2 : No (I thought it was written with the savage ability description).

I was curious about Q2 as well, because the reminder text for Savage doesn't indicate that. (Whenever this unit is dealt damage, deal X damage to target unit in any corresponding zone) If you still have to be alive upon being dealt damage it should probably say so. I've been playing it where they have to survive because that is the general consensus, but it makes it much less a good ability.

They clarified it in the rules sheet for March of the Damned under SAVAGE X:

"It is important to note that the unit with the Savage keyword must survive the damage it was dealt in order for the Savage keyword to trigger."