Those things which render the Salaah invalid

Q: Can we offer Qiyaamul Layl while holding the Quran and looking inside and reading?

Q: Sometimes I go straight to prayer after I make wudu and some left over water from my face falls into my mouth. I heard that drinking during prayer invalidates prayer. Apparently I did not deliberately drink the water that falls from my face into my mouth and it is almost impossible for me to stop myself from swallowing it along with my saliva once it gets into my mouth. What should I do?

Q: I have been amongst the Muslims who have rarely prayed, but now I started praying. I don't know some words or didnt memorize some words. Is it permissible for me to pray with a paper beside me explaining all the actions and words of Salaah?

Q: Is it permissible to have a wallet in one’s pocket while praying salat? The reason I ask this question is because there’s a chance that dollar bills in the wallet may have traces of fecal matter on them as they are used inappropriately in strip clubs.

Q: I came across that if I pray for something during my salah, my salah becomes invalid. I have done this many times such as, I prayed ya Allah! My wudu shouldn't break or ya Allah! Give me concentration..does my salah become invalid? 

Q: During salaah, if someone swallows snot that comes from the nose into the mouth, does it break salaah?

Q: Does laughing audibly with your mouth closed during salaah break your wudhu and salaah?

Q: I drank honey water. After about five minutes, I gargled my mouth but I didn't gargle the back portion of my mouth. I read my salaah and while reading, I had a sweet taste at the back of my mouth and I swallowed my saliva. Is my salaah valid?

Q: If one ate food right before praying, and can still taste the food in their mouth even though they cannot feel any food particles, just the taste, can they swallow it during prayer?

Q: If I find out something in the corner of my eyes after finishing salah, do I have to repeat it?