Prayer

Probably they have an illness in their backs

This athan you hear is exactly the same athan that was at the time of the Prophet salla Allahu alaihi wa sallam.

From Hudhayfah – that performed prayer with the Prophet (Sallallāhu ‘alayhi wa sallam) and he used to say between the two Sajdahs: ”‘Rabbighfirli, Rabbighfirli’ (O my Lord! Forgive me, Forgive me). [Ibn Mājah with a hasan sanad]

It is permissible to pray your night prayer in the format you stated. If sunrise is at 5:19, praying fajr at 5:00 is too late and you have to pray it earlier.

You can pray as many rakkah you want providing that you do not perform another witr.

If you pray it, Allah will reward you. if you don’t pray it, Allah will not hold you accountable for not praying it.

It is not recommended as it would distract you but it is permissible.

It should be done in any prayers that have two tashahuds.

No, this is recommended but as long as you say rabbi ighfir li, this is sufficient.

You must try to figure the direction of the qiblah by a compass. You should also pray standing up. If this is not possible, you may pray sitting down. If you can’t pray sitting down to the direction of the qiblah, it is ok to pray due to necessity.