I have received the following helpful and informative comments on this mural from Diane M.
The man with a staff and a scallop shell attached to his brown robe is the apostle James, son of Zebedee. It is a long tradition that James, after Pentecost, made a voyage to Spain to preach the Good News. When he returned to Jerusalem, he was put to death (Acts 12:2). However, eventually his remains were returned to Spain (so says the tradition), where they are now in the Cathedral of St. James in Campostela in northwestern Spain--not far from the sea--the end point of the medieval pilgrimage route. The scallop shell became a symbol of the pilgrimage, as well as for St. James himself.
The image of Mary and the infant Jesus is also related to this tradition of St. James. The story goes that he was discouraged in his missionary efforts in Spain, and had begun the journey back to Jerusalem, when the mother of Jesus (who was then living in Jerusalem, Acts 1:14) appeared to him in a vision to encourage him to continue preaching the Gospel in Spain. The depiction of Mary is honored under the title of "Our Lady of the Pillar" (which you can see in the mural).