Is my son who was breastfed one filling time by my aunt considered a brother to her children?
The baby who was suckled five sporadic times by a woman is considered a son/daughter of hers.
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.
What is the ruling on someone who perform their prayer after finishing it because they believe they missed a Rak'a, a prostration, or that they did not perform it correctly (thinking their prayer was invalid)?
If he was sure that his prayer is void then reperforming it is an obligation along with figuring out the reason of invalidity so long as this wasn't out of uncertainty. And Allah Knows Best.
Is Aqeeqah due on the miscarried embryo?
No Aqeeqah is due on the miscarried embryo.