The significance of the violet vestments? Perhaps because violet is the color of votive masses of the Passion and of the penitential rites.
Violet vestments are worn for Requiems in most of Europe, (optionally) having replaced black after Vatican II - as appropriate for pentitential prayers being offered for the purification of the soul of the deceased.
The use of white vestments at funerals is unknown outside the United States (and countries influenced by US practices, e.g. Canada, Australia).
Red for papal funerals: the traditional color of papal mourning.