Placeholders are broken in mirror mode, they are supposed to be fixed in the dev version, but afaik it still has issues so we need a new version. Temporary fix would be to disable placeholders and remove the existing ones.
It should if you can cast ardougne teleport (read the scroll not just receive it)
The webwalker is a bit slow sometimes, but it shouldn't get stuck, give it some time
They usually turn auto retaliation on right before the fight
It looks like the quest has already been started (probably on last stage before completion actually), not all quests are supported in a previously started state