Four rakaats after Zuhr and Isha

Q: Great virtues are mentioned in the Ahadith for praying 4 rakaats after Zuhr and Isha.

Should one perform these apart from the confirmed 2 rakaats sunnah that are prayed after Zuhr and Isha i.e. first 2 rakaats and then 4 rakaats? And these 4 rakaats should they be prayed with one taslim or 2 by 2 rakaats?

Four Rakaats after the Fardh of Esha

Q: Praying four rakaats after the fard of salaat Esha is mentioned in Ahaadith. Its mentioned that the virtue is that one will gain reward as having prayed these four rakaats on Laylat al Qadr. There are both Marfu and Mawquf reports regarding this. Should this be prayed after the 2 rakat sunnah muakkadah as adding 2 rakaats seperately or adding 4 rakaats either seperately or in two sets? 

I read in Qutul al Quluub that Ibn Masud (RA) did not like to pray after the Fard a same amount of Nafila rakaats, they would pray Isha and thereafter 2 rakaats and thereafter 4 rakaats. Is this true?

In Musannaf Ibn Abi Shayba 2/206 there is a report from Umar (RA) that he did not like to pray after Jumuah the same amount of nafil i.e. 2 rakaat. What Ibn Masud (RA) would do, is that 2 rakaats and thereafter 4 rakaats with one taslim?

Going into ruku' thinking that the Imaam made takbeer

Q: While praying Salaah in Jamat (congregation) a person was standing far from the Imam and also there were no speakers. At one point the person thought that Imam Saheb said Allahu Akbar, and so he was going to ruku. As he was doing so he found that the rest of the muqtatis were still standing (the person in concern heard it wrong) so he again stood up. Now my question is that is the Salaah of the person, in concern, valid or should he repeat his Salaah?

Certain things I heard when attending Hajj classes

Q: I recently heard from a Moulana whose name I will not mention and he does Hajj classes that when you are flying to Mecca for Hajj then:

  1. In the Plane you can sit in your seat a read your namaaz as you are flying North and facing Qibla! Can this be done?
  2. When making wudhu in the plane you can make massah over your woollen socks! Can this be done?
  3. If you make wudhu in your room and then go to the Harem and you then break wind or go toilet your wudhu does not break due to the massive amounts of people in the Harem and it would be highly inconvenient to go and try to make wudhu again in the Harem! Is this a correct statement?