Questions about an imam

He is tired after work and does not want to pray in congregation

The right side of the row is better than the left

Should he put the back legs of the chair in line with the row (when praying)?

One who comes into the mosque joining one who has stood up to complete the rak’ahs he missed

The imaam was accused of reciting Qur’aan incorrectly; what is the status of past prayers?

How should one person who is following the imaam stand in relation to the imaam?

Praying behind someone who works in a riba-based bank

How should one who has caught up with the congregation in the last rak’ah of Maghrib complete his prayer?

The member of the congregation has to follow his imam with regard to matters that are subject to ijtihaad