Surprised that you didn't talk about Rainbow foil Spellbound creepers sitting around the $127 to $130 range but Near Mint Cold Foiled Spellbound Creepers are at $130. In fact I would say that now is the best time to jump into runeblade financially. This is the lowest prices I've seen for the class in probably forever. I know I did. Also helps that both Viserai and Vynnset use the same equipment pieces so if you get the gear you can basically play both heroes relatively cheaply.
I don't think chorus of iron song will pop all the ward. I think it just pop the ward that would prevent it but it still won't prevent it. So let's say it attacks for 3 and you have ward 3 and ward 4 on the arena, it'll pop the ward 3 and you'll still take 3 damage, but the ward 4 should still be there. I could be wrong though. But that's how I interpret it.
Every Instance of Ward will try to prevent damage "at the same time" on the stack, but as a player you get to choose which one triggers first, so in essance you can choose what Ward pops and when. "Damage can't be prevented" essentally bypasses all instances of Ward, but the Ward will still try to trigger, and will repeat the process until you run out of Ward sources. That's why Vynsett/Prism is so lopsided, you eat though Prism's figments and Spectral Shields with one Runechant.