If a person wants to stay 10 days or more in a place, in this case prayers should be performed complete and the person must fast. And if this person wants to stay less than 10 days then prayers should be performed shortened and the person cannot fast. The beginning of 10 days is from the moment of entering the destination, for example from noon of the first day of arrival until noon of the next day is considered as one day.
There is no issue with doing this, but if that person doesn’t join the congregation before rukū‘ of the first rak‘at then his/her right is voided.
He should perform the qaḍā of prayers (i.e. perform them again later as compensation) that he has performed completely.
Such fears and doubts are the insinuations of Satan. Don’t pay attention to that and attend the congregational prayer continuously.
He/She should recite them in a low voice.
If other people consider you just then there is no problem for you to be Imam of congregation.
It is better to recite tashahhud or other dhikrs while in tajāfi posture.
Attending their Friday Prayer with the intention of creating a great unity among Muslims is good and suffices in lieu of noon prayer on Friday. Furthermore, under such conditions, there is no issue with prostrating on carpet.
It is permissible.
Travelers have the right to perform their prayers in al-Masjid al-Harām and al-Masjid al-Nabawi and also all of Mecca and Medina complete or shortened and complete prayer is better and there is no difference between old and new parts of Mecca and Medina.
If the same illness led to his death and he was not able to perform the qaḍā of his prayers and fasts then there is no need to perform their qaḍā. However, if he regained his health and was able to perform them but he did not, it is obligatory on his elder son to make up for them. But those that he had performed incorrectly although it is not obligatory for his elder son but he had better perform their qaḍā.
The itinerant distance is the criterion for the calculation of distance in religious issues. The reason for this ruling is that what could generally be understood from traditional proofs (ḥadīths) is the itinerant distance which is calculated based on the normal way traversed by people. This is particularly emphasized because usually the direct way between two locations is shorter than the normal itinerant distance between them that people usually wend. Therefore if the direct way were the criterion for calculating distance in religious issues then it should have been explicitly mentioned in narrations.