Learning a portion of the Quraan as mahr

Q: I'm getting married in June Insha-Allah. When my parents were discussing the mahr, I kept a request in front of my in laws and my husband that instead of money I wanted to be gifted with a Surah from the Quran which will hold a value of living a good life after marriage and adding barakah to our life. So me and my husband will be memorizing it. Is it a valid point?

Divorcing one's wife while living in another country

Q:

1. I need to issue a divorce to my wife but she is in my home country and I am abroad, can it be done via video call?

2. If I say it 3 times is it a valid and will the divorce be final ?

3. She has 2 kids from a previous marriage (their father is no longer in their life), after divorce, do I have any rights to the children who are not biologically mine? If so what are my rights?

4. Please advise me on the correct way to issue the divorce to my wife who is living in a different country since I do not have the means to go home to do it.

Suspending talaaq

Q: I told my wife that if she talked with her family members on her mobile except her mother and father then she will be divorced. If in case she talked to anyone then what will be the situation? Will she be divorced? I said only once talaaq in case she talked with them on the mobile.