Salat al-Jama’at

Islamic Shariah contains rules to organize the Muslim society in

all the dimensions starting from the personal life to the family life

to the social life and to the whole humankind relationship. Rules in

Islam do not mean insult but it means organizing the society in the

best way for the interest of everyone.

Illegitimately born child has got rules in Islam which aim to keep

him/her away from the public criticism. As the child did not commit a sin

and he/she should not pay for the sin of his/her parents.

The illegitimate child in Islam is kept away from leading the public

because that will make him a target of criticism and abuse from people

who will say that he was born from illegitimate act.

Islam also does not want to legitimise any illegitimate act. That is

why the child born from an illegitimate relationship cannot be a

leader in the community because that will encourage some people to go

for illegitimate sexual relationships.

An illegitimate child is not allowed to be Marja’ of Taqleed. He can

be a highly educated scholar but he cannot be Marja’ of Taqleed.

That also is not only for him but also for other respected persons in

the community like our respected ladies.

If a pious and highly educated female Islamic scholar becomes a

Mujtahidah, her own son or brother cannot follow her in Taqleed

because one of the conditions of Marja’ of Taqleed is to be a man.

And also for leading the Jamaat prayers, the congregation prayer, one

of the conditions is that the leader of the congregation prayer must

be a man and must be born from a legitimate marriage.

Islam does not allow us to pray behind pious ladies like our own

mothers. So that  does not mean any insult to our mothers but it is part of

organisation which must be followed, and that is similar when we are not allowed to pray behind a person who was born from an illegitimate relationship.

That does not mean that we are punishing him but Allah SWT wants the

organisation of the society to go on to avoid pointing the fingers to

such persons and also a way from legitimising an illegitimate sexual

act which took place.

An illegitimate person can be a lover of the Ahlul Bayt (AS) and will

get his full reward for all his good deeds because it is very clear in

the Holy Qur’an that (لا تزر وازرة وزر أخرى) “No one will carry the burden of

the act of others”. So the child who was born from an illegitimate

relationship will never carry the burden of the sinful acts committed

by his parents. He will get the reward of his good deeds like any

other person.

In fact Islam has kept the respect of such persons to keep them away from

the public leadership and observation so that their life can go on like any other person

and they will get the reward of their good deeds like any other

person.

Wassalam.

The level of the stand of Imam al-Jama'ah should not be higher than the level of the people praying behind him. He can stand lower than their level but not higher. 
'Wassalam.

We must help him as much as we can even if his situation requires us to break our Prayer to help his life or safety.

Wassalam.

Praying in congregation is highly recommended and the reward of every
Raka’at of it is multiplied by thousands of times. If you are in a
place where congregational prayers are held and your not participating
in it amounts to an insult to the Imam of the Jama’at or the
Mo’meneen, it will then be sinful not to participate in the said
congregational prayers.

There is another case, when the person does not know how to pray
individually or cannot recite the Qira’at properly, then he must join
an available congregational prayer.

Wassalam.

If the time of congregational prayers does not allow you to perform Nafilah of Zohr or/ and Nafilah of Asr, then you can perform the Nafilah after the Jama'at prayers is over, with the Niyyah of Qadha.

You will then get the reward of Jama'at and the reward of performing the Nafilah.

If you have little time which will kot be enough to perform the whole eight Rak'ats of the Nafilah, you can perform few Rak'ats like 2 or 4 Rak'ats.

Wassalam.

As far as the person is Baaligh, there is no restriction on age after being Baaligh.

Aadil is the Mo’min who usually abides all rules of religion and avoids all sinful acts.

If he for any reason commits any sinful act, he must repent and seek forgiveness, then he will return to the state of Aadil.

Obviously, all other conditions of Salatul Jama’ah must met.

Wassalam.