How are those killed in wars punished with the torment of the grave if they are not buried?
The torment of the grave refers to the suffering that the deceased experiences between the day of their death and the Day of Resurrection, which is called the Barzakh period. Similarly, it includes the blessings of the grave, whether the deceased is buried or not. And Allah The Almighty Knows Best
Is it permissible to use the term 'Al-Jalalah' (Majesty) for anyone other than Allah, The Exalted?
In the Arabic language, a man of dignity and reverence is described as 'Jaleel' (noble), and similarly, an elder or a woman of dignity may be described as 'Jaleelah'. In such contexts, one may use the title 'His Majesty' or 'Her Majesty.' However, the Majesty of Allah, The Exalted, is unlike the majesty of humans, just as His hearing is not like our hearing, and His sight is not like our sight. And Allah The Almighty Knows Best.
Is performing Umrah an obligation for who is capable. Is he accountable for not performing it in this case?
Umrah is an obligation once in a lifetime for every Muslim. When physical and financial ability is present, it is preferable to perform Umrah, as well as Hajj. If one can afford to perform Umrah but not Hajj, then they should begin with Umrah, especially since Hajj nowadays is not accessible to everyone who wishes to perform it. In contrast, Umrah is more open and easier to undertake. And Allah knows best.
Is it permissible to pray with a heater (stove) in front of me?
There is no harm in praying with a heater in front of you, as long as you do not intend to venerate the fire or imitate those who worship it. And Allah Knows Best.