I have been offered a job in Australia and the company is prepared to sponsor me on a 457 visa. Please advise on the following:

1. I was convicted of fraud charges 11 years ago, I had 2 years house arrest as sentencing. I have since had the criminal offence pardoned off my record so now my police record is clear. When filling in the application is it really necessary to mention this? I have not been in any other trouble before or after that. Is there a way that immigration will find out about the offence?

2. My wife has rheumatoid arthritus, will this negatively effect the outcome of the visa application if we put it on as a medical condition?

3. When applying for a 457 visa how long is the whole process more or less from start to finish?

4. Do I need unabridged birth and marraige certificates for a temporary visa?

5. can you please tell me what exactly was requested by immigration for the medical requirements for anyone who has applied for a 457 from South Africa preferably.

Thanks