Prayer

What is before the Fard should be prayed before it and it can’t be made up unless there is a legitimate reason for skipping it.

If you are referring to night prayers, yes you can but you shouldn’t do that as regular basis but rather once every while. But if you are referring to Sunnah prayers, this is not permissible

You must not break you prayer unless it is an issue of great importance as in the case of a child about to fall from the table or harm himself with fire.

You should not.

If there is no legitimate reason, it is a sin.

You should try not to annoy those beside you by lowering your voice so that only you can hear it.

The 3rd person should pull back the 2nd person and both should pray behind the Imam.

Your toes must touch the ground and should be bent while pointing to the Ka’abah. That is why it is wrong to be erect on the ground. They should be bent.

Through Repentance and lot of voluntary prayers.

We can refute this by saying that the Prophet salla Allahu alaihi wa sallam used to raise his hands in prayer. This hadeeth quoted is referring to raising the hands while in the sitting position when offering salam to the right and left.