Justice of peace (Canada)

Not sure if it’s the same everywhere, but I’m in Canada. My fiancé & I are doing Justice of peace to get married in September.

He’s planning on bringing some family & I probably will too. Is that allowed? Has anyone ever did Justice of peace?

Also, I need a cute little white dress to wear. Any ideas where I can order one? Will look into bridal shops but, would like to look online! 😊