Various Masaail on Qadha Salaah

Q:

1. As a youth, someone made an oath to not do something and they did it, they then fasted 3 days to expiate the oath (as they were unable to do anything else). Later that person apostatised from Islam but came back to the Deen. Do they have to redo the expiation for the oath broken? No oath was made since that time. 

2. Also, in terms of salah missed, are salahs missed over years must be made up by someone who Apostatised but later came back to the Deen?

Q: A person used to be a thief and had stolen over $100 000. He does not have any of the wealth left and has about 7 years of qadha salaah. He has reformed his ways and wants to gain nearness to Allah Ta'ala. How does he compensate for the $100 000 he stole? How does he perform the 7 years qadha salaah in a timely manner?

Q: I have three days worth of qadhaa salaah left from 2017. Is it okay if I delay making them up? Maybe if I read one salaah each day or, make up some salaahs one day then miss the next day, thereafter make up some other day, etc.?

Q: I offer qaza prayers of the prayers which I did not offer correctly 4 years ago. I mistakenly offered 3 rakahs of Asr qaza instead of 4 rakahs and then offered Maghrib qaza. Will I have to repeat the maghrib qaza along with the Asr qazaa?

Q: Should qaza namaz be offered in seclusion (so that not to be amongst مجاھرون) or it can be prayed in Masjid or in front of people if they don’t get to know one is offering a qaza namaz?

Q: I have a lot of qadha salaah. Is it permissible to read all the fajr qadha salaah first and then all the zuhr qadha salaah and so on. Or should I read it in order: fajr zuhr asr maghrib esha fajr zuhr....

Q: Can I perform Tahajjud, ishraaq and Duha Salaah even though I have Qadha Salaah? Or should I perform Qadha only.

Q: If somebody had missed a lot of prayers in his life and then he performs hajj, is he required to offer qaza of previously missed prayers or not?

Q: What is the quickest way to perform qadha Salah and what can be left out in the qadha Salah? 

Q: I started praying five times a day. Now I realize that I lost almost 25 years of praying. So according to this I was praying all this month but not regularly so Ramadan regularly praying almost praying for other days as well morning. Was it as well so I feel almost 10 years has been done now remaining 15 years prayers out there so I calculated for 15 years. So I need to clear 5475 pending prayers it is just an approximately figure please suggest advise me on this one