Those things which render the Salaah invalid

Q: Will the prayer be valid if some miswak fibers unintentionally remained in the mouth and were found after Salaat?

Q: Can an imam lead Taraweeh Salaah while looking at the Quran on a watch? As you know now there are smart watches. Those smart watches can automatically scroll the mushaf, so you don't even have to move or touch the screen. What's the ruling regarding this?

Q: If one's phone rings during salaah and the ringtone is musical, can one remove the phone from the pocket and pouch in order to switch it off? If one removes the phone to switch it off, will the salaah break?

Q: What is the ruling on person who uses his hands for itching, folding sleeves, etc. during prayer? When will prayer be invalidated?

Q: What is the ruling if a person lifts up both his legs during sajdah? Is the prayer invalidated?

Q: What is the ruling on the person who lifts his feet of the ground during sajdah? Is his salaah invalidated?

Q:

1. Is it permissible to hold the Quran in one's hand in Salah for reading so that one can read unknown surahs after sure fateha.

2. Is it permissible to read the whole tarawih prayers (alone) and in other prayers.

3. If not, could you please tell me why we should not do it.

4. Why do people in the haram hold the Quran in their hand and read or read from the phone in their salah.

Q: While in sujood, can I make dua in my own language? For example, I ask Allah's help for my work, or ask for betterment for my family's health or ask for jannah? If yes then in nafl sujood only or even fard/sunnah?

Q: If your mucus/phlegm has become sweet because of something sweet you ate then will it be okay to pray in that condition? Like in Ramadan when everyone drinks milkshake and eats dates when they break their fast and then they just wash their mouth out with water and stand up for Maghrib Salah even though their mucus is still sweet and the back of their throat is still sweet. Sometimes your mucus remains pink even after you wash your mouth out. What happens if you swallow this pink mucus during salah? Is it sufficient to quickly rinse out your mouth with water before salah or should you wait until the sweet mucus goes away? Sometimes I only break fast with water then eat after I pray to avoid this problem. What is the best way to deal with this?

Q: In fajr farz on the last rakat I made a mistake and I believe I got kind of mad and smacked my lips in the salaah but then I fixed my mistake. Is this fine?