As mentioned the holiday visa will need to be sponsored, and by you personally is better than by your business.
Again as mentioned the visa will state no work and no further visa application in Australia (must return to Thailand)
Aussie gov also want to see evidence that she will return to Thailand if on holiday visa, long term employment, care for children/mother etc, owning property etc.
If you’ve been married 11 years I’d expect a permanent visa to expedite.
I assume you must be able to show multiple and regular visits to Thailand with truckloads of pics of you two together with her family, at temples and doing tourist things etc ?
Why hasn’t she been to Australia before though ?