1- The husband’s share will be 1/4 of it, and the remaining 3/4 will be split equally among the 4 daughters. So the husband receives 25% and each daughter receives 18.75%.
2- If the father dies, his current wife receives 12.5% of everything he owns except the value of the land (so she inherits from the building value but not the land value). And the daughters receive 21.875% from their father.
3- If the father dies and he has a new child from his wife, and if the child is a girl, then the new wife will inherit 12.5% from the husband, and the 5 daughters will receive 17.5% each from the father. So the baby girl will receive as much as the older ones receive. If the baby is a boy, then each daughter will receive 14.5833% and the boy will receive 29.16667% of the share.
4- They should fight for their Haq. If fighting for their Haq leads them to be unsafe or be harmed, then they should not. But if they can then yes it’s their right. But remember that they will have a Haq if their father dies, not when he is alive.
5- Yes a daughter can enter her father’s house when she wants, but she cannot take any of his belongings without his permission. Now if the only way to secure her right to the house (if her father dies) is to get a copy of the house records or deed, then yes she can do that.