I have one clergyman who is on the staff of my church. He will assist at the memorial service for my brother – whom he did not know.
I have another clergyman who is a personal friend of mine (he was the chaplain at my college and we have known each other on and off for almost 50 years). He offered to memorialize my brother whom he did not know. But he has worked up a liturgy and will use the info I have given him about my brother.
Also there may be someone who plays the piano for one hymn.
I need to know how much the honorarium should be in each case.
First, I am very sorry for the loss of your brother. I hope that you and your family will be comforted by the memories of his life.
To answer your question, an average clergy honorarium is between $150 and $300 depending on the time involved with the family and performing at the service.
Since you have two clergymen with various degrees of involvement and relationship to you and your brother, I would pay the primary clergy more than the assisting clergy, who I am assuming will have a minor role. The amount for each could be something like $150 – $200 for the primary clergy and $100 for the assisting clergy, but you will ultimately need to decide this based on the effort and caring support each will put into the memorial service.
As for the pianist, that honorarium is a smaller amount, generally around $50 – $75, but for one hymn I think you would be fine with $50.