You should be ok or did you get a paper notice / violation stamp into your passport? In that case it might be good to get a new passport in general as other countries don’t like such stamps either.
When was that overstay? Have you left the country already and got stamped out? Your total amount of overstay days is below the 90 days from whereon a ban applies provided you surrender yourself at the border and don’t get picked up anywhere. You can always apply but if a visa is granted is up to the diplomatic mission. Likewise, even an issued visa doesn’t guarantee entry if the IO finds prior violations that would warrant a denied entry.
No restrictions, however the official application rule is that you “shouldn’t” apply further out than 3 months prior to arrival. There is no way for them to check though since you can enter a random flight number/date when applying via evisa.
the real reason why I wanted a local insurance is that in case of emergency I don’t want to argue with them about payment. There was the case with the Taiwanese guy last year who died because the hospital didn’t treat him.
Their own. Apply as a dependent of the main DTV. You need to be a real spouse with paperwork though (marriage certificate), just common law and other undocumented relationships don’t work.