In Thedas death is not final unless you are a lowly peasant or random NPC. I wouldn't even guarantee that burning to ash will do it.
Don't bother studiously reading the codices to immerse yourself in the lore so you can role play your character properly because like as not it will be altered next time round.
Leliana values your opinion in inverse proportion to your status in the world. When she hardly knows you and you are only just getting going as Herald, if you ask her not to kill someone, she obeys dutifully. When you have carried all before you and people revere you as their prophet, you have confronted Corypheus, saved Orlais, been to the Fade and back and are viewed as one of the most powerful people in Thedas, if you tell her not to kill someone, she ignores you and cuts their throat.
You never get to ask people the questions you want to ask them because apparently the PC is an idiot and ignores evidence that any sensible person would want to query or share with their inner circle.
Andraste never got to Tevinter with her army; only in chains. Not to worry though because the Chantry has been supressing the truth about just about everything.