If your visa states "Multi Entry" you can come and go as many times as you like during the validity of the visa, each time being stamped in for 60 days
The only people being told to leave are those who were stupid enough to use an agent for something they could easily do themselves or those trying to buck the system. No big loss.
Shows how much they think of their wives and kids if they can't bring in just 40k per month, but can find the money to get a dodgy visa off a dodgy agent. I don't pay any traffic fines because I find it easier to stick to the rules.
She's probably not paying tax on the one you're in, so she uses the other address. As Robert says, immigration don't do checks on TM30 so I wouldn't be overly concerned
You can get a Thai insurance (although it's pretty useless as it has an excess of 200,000 baht) for around $300 Aussie dollars (7700 baht) which satisfies the requirements for the OA and OX. However, I get a decent insurance through an Allianz broker, who signs the form for me, and it's accepted by the Thai consulate in Sydney. I refuse point blank to stay in any foreign country without adequate health insurance, but there are so many cheap Charlie expats who work hard at avoiding insurance! Don't worry, I've done the research!