Nikaah & Marriage Issues

Q: Is marriage of a Sunni (Deobandi) girl valid to a Shia boy?

Q: I got married approximately 9 years ago. At the time my wife and her father wanted Mehr e faatimi as mehr. However I could not afford the mehr e faatimi at that time. They then agreed to a lesser amount but I told them that insha allah one day when I am able to then I will give her the full mehr e faatimi amount. This was just verbally said and was not written down. 

Alhamdullilah I am now in a position where I can give her the full mehr e faatimi amount. I would like to know if I should give her the mehr e faatimi amount at that time (9 years ago) which was approximately R 12 500.00 or should I give her the mehr e faatimi amount of current value which is approximately R28 000.00?

Q: I am currently studying, but my future wife's father is sick. Some people suggested that I get married first and then continue studying. At least the father will see his daughter getting married. 

What I am confused about is, isn't it cruel if I haven't provided for her financially or spiritually? 

I think it will be difficult to finish college while working.

Q: Is it okay to make engagement posters on the engagement of a couple? 

For example: We are pleased to announce the proposal of:

Groom 

Bride 

Please advise.

Q: Is it appropriate to read a qiraat at a walimah venue where women are generally not dressed correctly despite being in a separate venue (from the men). 

Any additional advice for these kinds of occasions will be highly appreciated

Q: I'm in the 5th month of my first pregnancy. The 4 heart chambers of the baby can not be seen and the doctor says that the baby has a big hole in the heart. The baby can die or will face multiple surgeries and may survive or not. We are not sure what to do and we don't have this much cash. Can I terminate the pregnancy or not?

Q: If one's husband has made nikaah without telling her and she found out about 3 months later. Her husband did not consummate the marriage and after consulting with his seniors, he regrets what he had done. However he is afraid to divorce the second wife due to backlash. The first wife wants to make dua that he leaves his second wife since he hasn't caused her to to become pregnant which will further complicate things. 

My question is, is one allowed to make a dua as such... "Oh my beloved Allah you create a good excuse for my husband to leave his second nikaah with aafiyah and you make it such that she finds a better spouse for her thereafter". 

Will this kind of dua be allowed?

Q: Can a woman have relations with her husband if she has istihaatha?

Q: Is it permissible to spend money on décor on the occasion of the waleemah? People spend a lot of money on flowers and draping the stage etc. Does this fall under israaf or is it permissible to do this if a person has the money and is not borrowing money to do it?

Q: Is it permissible for children to throw flowers on the bride on the occasion of nikaah?