Understanding「だってこうなるって」

Question

In Flying Witch chapter 2, Makoto asked her friend if she's too scary to her. The lines below are her friend's response.

違うってば

こないだのことでちょっと混乱してるだけ

いきなり、ほうきに乗って、空飛んでる人見たら、誰だってこうなるって

I have difficulty comprehending the bold part.

1. Is「だって」here the colloquial version for「だと(思っていた)」?

2. Does「こうなる」roughly mean "this is how it happened"?

3. What kind「って」is used after「なる」? I'm not sure if it's a colloquial quotation marker.

This is how I understand the third line

When I saw a person flying in a sky with a broomstick out of nowhere, I was like "who is that person?" This is how it happened.

Did I get it right here?

Answer 1

• 誰だって means "anyone" or "whoever". It's a colloquial variant of 誰でも. We say 何だって, どこだって, いつだって, etc., too.
• こうなる just means "to become like this", and こう refers to 混乱する.
• って here is a sentence ender meaning "you know", "come on", "I mean it", etc. I think it's etymologically a quotative particle with 言う omitted.

  大丈夫だって、きっと合格するって。
  Don't worry, I'm sure you'll pass.

So the sentence means:

いきなり、ほうきに乗って、空飛んでる人見たら、誰だってこうなるって。
Anyone would be like this (=be confused) if they suddenly saw a person flying in the sky on a broomstick, you know!