if the ones dying are the assassins, I don't know the way (if there's any) to prevent it. but if it's the magus or anyone else, then I do know. I DON'T claim the steps I did as the perfect one, but at least I managed to avoid any major character death :")
I always choose to prioritize the public, be wary of the nobles, and just be kind but still cautious of the peris. however, this will result in one locked dialogue in court scene. so it's still flawed, but I don't think it's a complete failure lol still trying to find the perfect steps tho
if you want a walkthrough, just let me know! I'm not an expert but I'd like to help ^^