There is absolutely zero value your wife could bring to a Thai company. I could go on and on and really on about why is that the case, but the major issue is that as much as Thais, Westerners are stuck in their ways. This is a strictly cultural thing, no offense.
As for the Australian property do not sell it. Rent it out and try to cover mortgage payments that way. Very easy to sell in Australia, very hard to sell in Thailand.