No
Sounds backwards to me.
It's absurd to draw such a general correlation.
It always depend on the person if he will pass a subject or not.
You'll certainly not have difficulty in physics and engineering BECAUSE you are good at math or economics; math, especially, is important in physics.
Not so sure about economics but you will need physics.
No, you have to be good at physics and engineering to be good at it. Engineering would require you to write reports, but to write a 2500 word report? It's about quality, not quantity. If you can write a good essay, then you should have no problem writing up reports for when you do engineering work - assuming you know what you're doing. If you're hopeless at writing essays, physics and engineering, then you're going to be bad at it.
No you will not fail.
no
Yes.
I'm good at Math and I passed Chemistry.
Of course, there isn't a reason not to, because mathematics is the language of economics, science and engineering(with the exception of computer programming).
Not normally, that describes most (of us) engineers,