yes "owing to x" or "due to x" x = the thing or circumstance, that caused y "owing to x we now have a y situation" "owing to x y will now happen" "owing to x we can't any longer have/achieve/expect/anticipate y" etc due to x can replace owing to x. owing as a debt" is a different thing entirely.

Yes.

Yes, but "due to" is less formal, and I think Americans would tend to use it rather than "owing to."

owing to and due to are both defined as adjectives meaning because of in all dictionaries. Debt is entirely different.

No, to owe is an obligation or repayment. Due to, is the result of something else. Can you use both terms in a complete sentence, so that I can better direct you?