Co-own.com.au only requires you to be an Australian resident eligible for a loan on your percentage.
Technically yes, but this would defeat the point of co-ownership. If you can comfortably afford to pay for 100% of the property, then you should consider buying outright.
Both co-ownership and shared ownership describe the same partnership in the property, both just using different terminology.
Rules vary from state to state, so it's advised that you get in touch with your states land office to check you're eligibility.
Expenses for the property are based on the percentage of the property you hold. A detailed list of each owner’s duties are outlined in the co-ownership agreement before entering the arrangement.