Travelling by train without purchasing a ticket

Q: I live in India. Previously I used to not take the railway ticket rules seriously. I used to enter railway platforms without a ticket (which is wrong and would be fined if caught). I have sometimes travelled in trains with improper ticket. Mostly unintentionally as the rules are very complex and so we end up breaking them without intending to. This would also have been fined for if I were caught.

Once I was caught by the inspector did not fine the amount stipulated by the government. Now I feel regret for all this. Is this a sin that we need to do tawba from? If yes, then would it be sufficient to do tawba in the heart or should I give also some monetary compensation for my violations ? (There is no proper government facility to collect fines for violations that go unnoticed). 

If I should give compensation, should I just pay the government the original amount that I should have paid? Or should I also give the fine that I would have had to give if I were caught? I am very confused as to what I should. Please guide me on this issue.

Conditional divorce in a letter

Q: Some months ago my wife got angry due to some family issues and went to her parents’ home but did not come back. I tried to bring her back but she didn't come. One day I sent her a letter that If you want to come then welcome a thousand times from my side otherwise consider this letter a divorce from my side. (I mentioned Talaaq, Talaaq Talaaq in letter). Decision is in your hands. Now I want to know whether divorce has happened after she got my letter or not?

Thoughts of showing off

Q: If you get thoughts, urges or daydream about showing off your worship to other people so they will praise you but you don't act on the thoughts or urges, would you be still a sinful? Basically they are just thoughts, desires and urges of showing off in your heart but you don't physically show off.

If you get thoughts or daydream or images in your mind of shirk and kufr but never act on them physically, they are just in your mind, would you come out of Islam or become a disbeliever?