The scientific term would be “ulnar deviation”.
True ergonomics would be more along the lines of Dactyl Manuform or Corne with tenting.
The pronation and extension of the wrists in addition to ulnar deviation is very similar on both row staggered and ortholinear boards, the main difference being that there is less space from key-to-key with ortholinear layouts, but that doesn’t mean that it is more ergonomic.
I can’t imagine typing in a layout like the one you are currently using and having your wrists ‘perfectly straight’ unless you had incredibly narrow shoulders with your elbows tucked into your rib cage. I have fairly petite dimensions, and even for me they would be nowhere near ‘perfectly straight’.
No, that is present at any point on Ortholinear. Here’s some random images from Youtube videos: Even with the split ortho keyboard, ulnar deviation is present. For that to be avoided with an Ortholinear board, you would have to have inhumanly narrow shoulders.
Unless your proper form is literally sticking your arms out in front of you like a stereotypical zombie, I don’t know how one could feasibly achieve this.
There absolutely is and it is easily observable.
I’ve told you nothing about how I type, so any assumptions you are making here are based on something else.