The whole JW notion of thinking they must set themselves apart from the world is so inconsistent. As the OP pointed out, the wearing of a white dress was a trend that Queen Victoria started so that she'd stand out and be more visible among the throngs of people at her wedding. It was also meant to signify purity and virginity.
Wearing a ring on the left hand had non Christian superstitious origins and the wearing a diamond ring specifically which came into vogue when the diamond cartel did a mass advertising campaign by giving diamond rings to celebrities and then showing this to be a trend among the rich and famous hoping that the public would try to emulate them and it worked. JW's followed suit even though they were emulating the world.
Marching down the aisle of a religious building (church) to a religious song (hymn) was a practice started in Christendom as was wearing a garter and throwing a bouquet.
JW's pick and choose what is or isn't "worldly" and ignore anything that shows their choices don't make sense.