Is Tatbir permissible? If one has made a vow to perform Tatbir, what is the ruling?

I read somewhere that if a girl is independent in all matters of her life, she can conclude temporary marriage with a man without her father’s permission. In such a case, the marriage contract is valid, though she has committed a sin. Please explain more.

What is the ruling on giving a speech or presentation in university classes where non-mahram students are present and one has to stand before them? This would result in them looking at her, though she does not intend to draw lustful intentions. Take it into account that most students know each other.

Is temporary marriage with a girl allowable without permission from the girl’s father? Stipulating that the father’s permission be sought makes such marriage impossible since no father gives such permission to his daughter and this would result in sinning.

1. How do “qadha” and “qadar” change the course of events? Aren’t they in contradiction with man’s free will? What is fate? 2. Does God change our fate because of our deeds? Do our actions cause any change in our future? 3. If one can create problems for others through writing certain spells, wouldn’t it prevent the victim from exercising his free will? Why does God let some people exercise witchcraft? 4. Does offering prayers change one’s future?

What is the ruling on chatting on the Internet?