Sunnats and aadaab of wudhu

Q: Is it sunnah to renew the wudhu before sleeping or will the wudhu made previously suffice?

Q: My face is oily. When I am performing wudhu, some of the oil of my face gets onto my hands. Do I have to rub my hands with water to ensure that water gets underneath the oil and reach my skin?

Do I have to rub any part of my body if the oil of my face gets onto them (for example my forearms, my feet)?

In that same logic, if oil from a part of my face (the left part for example) get onto or mixes with the oil of another part of my face (the right part for example) do I have to rub that area with water (the right part of my face)? 

Q: If a person performs wudhu by spraying water using a spray bottle and wiping the required parts without water falling on the ground, will the wudhu be valid? Is there a requirement that water should fall on the ground while washing in wudhu?

Q: How many litres of water would Nabi (sallallahu alaihi wasallam) use for wudhu and for ghusl?

Q: If the nail gets long and were not cut in a week, will the wudu and namaz still be valid?

Q: Please let me know all sunnah and mustahab duas that should be read during each step of wudhu. The dua while washing hands, gargling, cleaning the nose and so on till washing the feet.

Q: What is the preferred method of making khilaal of the toes?

Q: I came to know about the hadith of Nabi Muhammad (sallallahu alaihi wasallam) that wudhu is not proper if we don't say Allah's name before wudhu. I didn't know about this. So I mostly made wudhu without saying Allah's name. Was my wudhu accepted and am I sinful?

Q: When should khilaal of the fingers be made in wudhu? Should it be made after washing the arms till the elbows or after making masah of the head?

Q: I just got 4 of my wisdom teeth removed and my gums are in pain and constantly bleeding. If I rinse my mouth a bunch of blood comes out. So how do I make wudhu, and how do I pray?