The Meaning of the Hadith “Cleanliness Is Half of Faith”

I am sorry for burdening you with all these questions at one time. Try to answer as many as you can if you think the whole lot is too much.1) what is meant by the hadith "cleanliness is half of faith" ? Can you please explain what aspects of faith does it cover and what sorts of cleanliness, physical and spiritual, does it mean ?2) which twelve leaders does the following hadith from Bukhari refers to Volume 009, Book 089, Hadith Number 329.narated By Jabir bin Samura : I heard the Prophet saying, "There will be twelve Muslim rulers (who will rule all the Islamic world)." He then said a sentence which I did not hear. My father said, "All of them (those rulers) will be from Quraish."3) What are our duties towards the members of the Holy Prophet pbuh's family as we are told to observe them in the following hadith from Muslim Book 031, Hadith Number 5920. "...I am leaving among you two weighty things: the one being the Book of Allah...The second are the members of my household I remind you (of your duties) to the members of my family..."4) I was of the opinion that all children who pass away before reaching the age of puberty will go to heaven. However, the following hadith from Muslim gives a different impression. Please explain. Book 033, Hadith Number 6436. 'Aisha, the mother of the believers, said that Allah's Messenger (may peace be upon him) was called to lead the funeral prayer of a child of the Ansar. I said: Allah's Messenger, there is happiness for this child who is a bird from the birds of Paradise for it committed no sin nor has he reached the age when one can commit sin. He said: 'Aisha, per adventure, it may be otherwise, because God created for Paradise those who are fit for it while they were yet in their father's loins and created for Hell those who are to go to Hell. He created them for Hell while they were yet in their father's loins.5) what is meant by "everyone is facilitated in that for which he has been created" in the following hadith from Muslim Book 033, Hadith Number 6400. 'Ali reported that one day Allah's Messenger (may peace be upon him) was sitting with a wood in his hand and he was scratching the ground. He raised his head and said: There is not one amongst you who has not been allotted his seat in Paradise or Hell. They said: Allah's Messenger, then, why should we perform good deeds, why not depend upon our destiny? Thereupon he said: No, do perform good deeds, for everyone is facilitated in that for which he has been created; then he recited this verse: "Then, who gives to the needy and guards against evil and accepts the excellent (the truth of Islam and the path of righteousness it prescribes), We shall make easy for him the easy end..." (xcii. 5-10).6) Muslims are asked not to cross boundaries in supplications and cleanliness. What are those boundaries ? 7) If I have a fever and someone asks me 'how are you?', then how am I supposed to answer him. Some one told me that if someone enquires about my health I am supposed to tell him my real health conditions. And I know that in all circumstances I have to thank God for whatever I have in whatever condition I am in. Given this, how should I phrase my reply that it becomes an appropriate answer ?JazhakAllah khair for your services Shahbaz