Paying for one's poor neighbour's renovations using zakaat money

Q: The following has occurred and I am not sure if it counts as my zakaat being fulfilled.

We have a neighbor who is a worthy recipient of zakaat. My parents were in the process of helping them amend some part of their home when my zakaat became due. I had informed them of it and so my mother gave the man who is doing the fixing, the money to buy the tools and materials with the intention of zakaat for our neighbor. It was not given to the man doing the fixing in lieu of his labour but rather for the material needed to fix our zakaatable neighbors house.

Is my zakaat considered as valid ?

Receiving the normal price of an item when returning an item instead of the discounted price

Q: If a person sells a certain item and a discount was given to the customer and thereafter the customer wants to exchange the item or be refunded for it, will it be permissible to subtract the discount given (proportionally)? If the discount is not reversed will it be regarded as interest?

Khula after 2 talaaqs

Q: Can a wife get 2 khula? 1st one was given after 2 talaqs because the husband wants a second wife. They then got married again and now she wants to go for another khula as her husband still wants a second wife.

Secret nikaah and publicizing it after a while

Q: I am a 53 year old divorced female. My first cousin is 62 and he is recently divorced. We are both single, and are considering making Nikah. Because our families are very close, we are afraid that if we have a public Nikah, and the marriage subsequently does not work, this will cause immense stress on the entire family. Is it possible for us to do a non-public / secret Nikah for a while and then if all works out, we will then tell the family that we are married.