Q1: What's the difference with "priest" and "padre"?
In some countries, and in the armed services, a priest or chaplain is given the title 'padre'.
Q2: I saw some people in the parade took a red flower. Could you possibly tell me what the name of the flower is? Why is it red? Is every colour of flower okay?
In China, flowers with red colour is a no-no in the funeral. We usually take white flowers.
There is a huge cultural difference here. As I understand, certain colours are regarded as 'lucky' in Chinese culture. We do regard white as traditional for the bride at weddings, and black for most people at funerals with regard to dress, but even this is far less strictly adhered to these days : apart from really bright colours, no one these days would be surprised if somebody wore coloured clothes to a funeral...nor in the offering of flowers in wreaths or other floral tributes.
It may have been a red rose, or gladiolus or even a carnation.