Sergeant Lemon, I know it's a lot, but please go back and read the thread - it's been done to death that the crew didn't just fly a heading of 360 when they meant 180. Language or no, we all use the same numbers - are you seriously contending that the crew "just" flew 360 in error?
1. Give a heavy jet multiple, rapid reversals of turn and pretty soon they'll appear on your scope to be "maintaining a heading".
Should some query have taken place? Absolutely. Though, not having your read-back of the instruction corrected would go some way to alleviate any doubt.
2. No. They did not "proceed(ed) to then carry on North"
3. Her traffic situation should not be a concern of theirs.
4. Speaking English, and translating it in your head to native language is not the same thing.
Yes. Yes they do, more for the loss of SA on terrain than for anything else...
As always, multiple factors, and players involved.