I did something similar but it was a mission.
I entered Aus with UK reg car, expired tax sticker (ran out whilst overlanding, and SORN'd the vehicle. This was a nightmare here as they wouldn't temp reg the vehicle without a valid UK Tax sticker.. Anyway)
1. Whilst here, I applied for Vehicle Import Approval. I had to write a cover letter for special consideration under extenuating circumstances. It says that VIA's are given to vehicles not on shore. But I entered under a carnet, and I said my original intention was to export back to UK but not situation changed.
2. Not sure, your call. My inention was to return to UK so thats what I put there.
3. After getting my exemption for a pre-charged equipment licence (this is still confusing, its to do with the AC gas) and with my VIA, customs in Adelaide signed off my carnet. And I got my 50% refunded.
4. I remember something on the back of the carnet about getting approval from the issuing body (RAC) to destroy the vehicle. In my understanding they would need to give permission first, then go to a crusher who will crush your bike and give you a certificate that says the goods have been destroyed.
5. In my opinion this cert of destroyed goods should be sufficient to get your 50% back, but its un-tested.
6. I would say No... Dont think it would comply with the wreckers Cert... Once again this is opinion only.
here is a little thread that I started a couple years ago... maybe something useful
http://www.horizonsunlimited.com/hub...ly-under-68737