well technically they never promise a non shoot playthrough they just said "player freedom" that imply alot of stuff.
Most of the missions are "go here and kill everything/everyone". You would not be able to do much as a non violent character.
No not really. Most quest require you to kill someone or something. I don't know if they lied but quest don't have different ways to complete like 3 and NV did.
Charisma stealth build ; let your partner kill them for you. See? no violence playthrough.
They said we could avoid killing a lot but most quest we must kill.
that doesnt imply a non violent play-through. That why i said they technically never promise a speech play-through, that is something ppl just got in thaie head that they want to do.