Everyone is gong to be different, there won't be a set lot of questions. Simply have everything printed out and your facts in your head, only you can answer honestly and factually
It seems moreover they are closing in on the requirements and ensuring they are respected. We have seen reports from people abusing the requirements and trying ways around things to gain the DTV. Of course the more people try, the more stringent the questions and requirements become. This is basic logic that any government would apply. Don't be surprised. Its not random, it's continual improvement to counter the continual abuse.
Read alot on all the legal sites so your fully abreast of everything and who is offering what, you have months worth of info to read up on and then list your questions. It's also a changing game with daily updates on embassy requirements, but the main criteria remains.
It's government they have agreements with lots of other governments to share information, I'm sure they would do some sort of background checks, wouldn't you!