Qiraat in Salaah

Q: Can we read two (2) separate Surahs in one rakat of a farz namaaz? For example, I read Surah Kafiroon and Surah Ikhlaas in the first rakaat of Fajr farz namaaz. 

Q: Could you please specify how to read all the rakaats of Zuhr Salaah:

E.g. Zuhr - Four Sunnah (Surah Faatihah and a Surah in all four rakaats) then four fardh (Surah Faatihah and a Surah in the first two and in the second two, only Surah Faatihah), then is two Sunnah (Surah Faatihah and a Surah in both rakaats) and last for Zuhr is two nafl (Surah Faatihah and a Surah in both rakaats).

Q: My question is regarding the order of recition of Surah's in namaz. We are students and I was the imaam for fajr. In first rakat, after Surah Faatihah, I recited Surah Nasr and in the second rakat, after Surah Faatihah I recited the first 3 verses of Surah Mulk. Was the namaz totally wrong and needed to be offered again?

Q: What is the sunnah qiraat for the different salaah, and is it sunnah to recite it in all the salaah (i.e. sunnah, witr and fardh) or only the fardh salaah?

Q:

1. During the fardh salaah of Zohr, Asr, Maghrib and Isha, can the imam omit Surah Fatiha in the 3rd/4th rakat (when there is time constraints)? Stand for 3 subhanallahs before going in ruku.

2. Also, when one is performing Salah individually can one omit for the same reasons?

3. What is the status of Surah Fatiha in 3rd and 4th rakaat? i.e. Fardh, wajib, mustahab etc.

4. Is there any hadeeth to support?

Q: I was sad for a moment during salah and I think my throat strained and my recitation jerked slightly. Is my salah fine?

Q:

1. When a man is praying maghrib alone, is it best for him to recite loudly or silently? 

2. If he chooses to recite loudly, should he also say the takbeers, samiAllahu liman hamidah etc loudly as well just as an imam would have done?

Q:

1. Can we skip surahs in between in salah? If not, for which salah (fardh or sunnat) can we skip surahs. Example, can I read Surah “Al-Kafirun” then skip Surah “An-Nasr” then recite Surah “Al-Masad” in first and second rakat.

2. How many surah's can we skip in between in Salah?

Q: I know that one should read longer Qiraat in the first rakat than the second rakat and that one should not skip an in-between Surah between rakats unless the rakat one skips is long. This applies to Fard salaah. My questions are:

1. What is meant by "long" Qiraat? Is this the number of lines or the number of ayaat?

2. Does the Qiraat have to get progressively shorter for the nafl and Sunnah rakats of Sunnat-e-Muakkadah and Sunnat-e-Ghair-Muakkadah as well?

3. Can you skip an in-between Surah in the Nafl and Sunnah salaah?

Q: Do we need to recite surahs in order as per the Quran Majeed?

If a person doesn't know this ruling before and afterwards he comes to know it, he recites in order, what is the ruling on this?