Is it permissible for me to name my daughter “Leen”?
“Leen” means “ease”, and there is no harm in giving your daughter that name.
Is it permissible for one to masturbate in order not to commit fornication?
This is called committing the milder of the two evils such as eating a carcass in fear of death, and this happens when committing fornication is very likely to occur.
If husband doesn`t pray, but wife does, is their marriage contract considered valid or not?
All perfect praise be to Allah the Lord of the Worlds. May Allah`s peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Not observing daily prayers is a grave sin, but doesn`t invalidate a person`s marriage contract. However, we advise you to save your husband from hellfire by convincing him to observe the prescribed prayers. And Allah The Almighty Knows Best.
Is it permissible for a person who has to make up for missed fasts to fast six days of Shawal(the month directly after Ramdhaan) before making up for the missed fasts ?
Yes, it is permissible for him/her to do so, but it is better that they make up for missed fasts first.