Supplications

Yes it is.

There isn’t any specific Du’ah. You should strengthen your Tawak’ul on Allah and to have your full trust and dependence on Him. If you do this, you will find that your attacks are much less frequent. Try to ask Allah to strengthen your heart and to prevent you from having these attacks.

You shouldn’t do this for your children unless they are ill.

When a person makes Du’ah for another Muslim so that Allah would forgive them, Allah accepts this Du’ah. If your question is whether this dead person knows about this Du’ah or not, he most likely does not.

You should pray with sincerity and full dependence on Allah. You should also make sure that your earnings are Halal. You should also choose the times where Allah is most likely to answer you call as in the between Athan and Iqamah and in the last third of the night.

One can supplicate and make Du’ah all the time by raising the hands and asking Allah whatever he wants.

There isn’t such a thing to my knowledge. Before the last sunset of the 13th of this month, all Takbeer related to Hajj stops.

No, this is not recommended

Du’ah al Qunoot is not mandatory. Therefore, you can make it and you can also skip it. it can be done before bowing in the last rak’ah and the majority prefer doing it after raising the head from the bowing position of the last rakah.

There isn’t anything as such. One must ask Allah for forgiveness a lot as this increases the chances of getting provisions from Allah.