Is it permissible to perform Hajj on behalf of one of the Companions?

There is no harm in performing Hajj on behalf of the deceased, but praying for the deceased is much better than performing good deeds. The Prophet mentioned that a person's deeds cease after their death, except for three: ongoing charity (Sadaqah Jariyah), knowledge from which others benefit, or a righteous child who prays for them. He did not mention performing Hajj or giving charity on their behalf.