32 is way past dependent age, and you will not be granted as dependent to her…since everyone is an adult minus the 3 year old
Yes you will have to all apply for separate DTV visas and each will have to have the required monetary amount in the accts.
if You get the DTV you cannot work in Thailand for a Thai company being a teacher, you will have to get a work permit to work, if police or immigration does a check and sees that you’re working illegally there will be repercussions for your actions