Conditions for the validity of Salaah

Q: A lot of people tell me that you can delay isha prayer till midnight, is this true?

Q: If I have filth on my clothes less than the size of a dirham and water touches it and the diameter increases from one dirham, can I pray in those clothes?

Q: I wear a trousers belt, it's leather. I don't know what kind of animal skin was used to make this leather belt. I heard that if you wear leather made with pig skin and if you pray salah with it, it wouldn't be accepted, it's nearly impossible to tell if the leather is pig skin or not because where you buy it, it doesn't says. Would my salah be valid? 

Q: I came to know by one of the dawat-o-tabligh elders that we can make intention of many different namazes (e.g: if we are praying ishraq then we can make intention of tahiyaatul wudhu, tahiyyatul masjid, salaatul hajat, salaatul taubah, etc.)

1. Is it true?

2. How many total extra niyyats can we make for a two rakat nafil?

3. Can we do the same for zohar, maghrib and isha nafl prayers?

Q: On a trip out of town that necessitated qasar salaah, my sister checked the qibla direction using 2/3 apps. 2 gave a certain direction and the 3rd gave a different direction. We thus read our salaah according to the qibla direction from the two that were the same. However on the day we were leaving, I was on the balcony watching the sunrise and realised the sun was rising on the exact opposite direction of our qibla direction. In my understanding the qibla direction is north east and the sun rises in the east which meant our qibla was incorrect. Is this right? This doubt is lingering on my mind. Do I have to repeat my salaah? 

Q: A fowl came into the home and soiled the carpet with droppings. Should I wash the soiled area only, or do I have to wash the entire carpet? If salaah was performed on the clean portion of the carpet before the entire carpet was washed, will the salaah be valid?

Q: Can we wear a leather belt in namaaz or not?

Q: I had to pray 4 rakaahs sunnat after the jamaat prayer of Jumuah, but I mistakenly made the intention of 2 rakaahs sunnah. After starting the prayer, I remembered that I had to pray 4 rakaahs, so I offered 4 rakaahs instead. Will my prayer be valid?

Q:

1. If beer, wine, alcohol touches my clothes, does it make them impure?

2. Is the prayer accepted while wearing such clothing?

Q: Is my Fajar, Zuhar, Asar, Maghrib and Isha valid if I pray them while azan is in progress?