Jamaat Salaah and Imaamat

Q: I have a few questions regarding a late comer joining salaah:

1.Is it important to recite sana once you standup to complete your prayer?

2. What if sana was recited when the person joined in the 2nd, 3rd or 4th rakaat

3. Due to misunderstanding and following someone, if a person follows a different procedure to complete the missed rakaats in salaah for a couple of years and now he comes to know correct Hanafi procedure, will his passed salaahs be valid?

4. Is the below procedure correct as per Hanafi mazhab: If a person joins jamaat salaah and says salaam at the end of the 2nd rakaat and after salam he stands up and doesnt read sana and treats this rakat as the 4th rakaat. He only recites surah fatiha and completes his salah. Is his salaah valid or does he have to stand up recite sana, surah fatiha and a surah to complete his salah?

Q: If any Imam chews tobacco (zarda plan), is my salat complete behind that Imam?

Q: If a husband and wife want to read salaah side by side and seperately (not in congregation), can they do so? I read salaah beside my husband several times and seperately (he wasn't leading me in jamaat). Are the salaah valid or should I repeat them? If I am reading salaah with my husband and he is leading me in congregation, then where should I stand? 

Q: If I joined the maghrib salaah in the last rakaat or while the imaam was reciting tashahhud of the second rakaat, then how should I perform the two rakaats that I missed, and when should I recite the thana?

Q: If an Imam is leading an obligatory prayer in the Masjid and an earthquake strikes severely, under the Shariah, should he not suspend that salah and ensure for human safety and not show heroism? Taking the cue from the ruling on rains and harsh cold weather and the Prophet (sallallahu alaihi wasallam)'s command to stay at home and pray, is earthquake not a bigger calamity? 

Q: I work in a hospital. The nearest Musjid/Musallah is about 5-6 km away. Alhamdulillah we have permission to travel for Zuhr salaah during our lunch break (Our lunch break is 30 min, but it takes about 40min to go for Zuhr salaah and come back to work) and have been doing so for approximately the last 3 years.

However there are colleagues from other departments in the hospital who are not always able to join us for salaah. Should we request hospital management to give us a room to perform salaah with jamaat, and encourage other colleagues to join us for jamaat, or should we continue to encourage them to join us for salaah at the musjid?

Q: Can a musallee reserve a place in the saff for another musallee?

Q: Can one follow the jamaat salaah of the Haram from the musalla in the hotel/hotel room?

Q: Can one join the saffs on the marble outside the actual Haram, considering the fact that there are huge gaps inbetween the saffs? 

Q: Can a hanafi follow the witr in makkah/madinah?