http://www.shaveicesupplies.com/ (http://www.shaveicesupplies.com/)
The person I spoke with at length confirmed there are no peanuts, tree nuts, potato, wheat, sorghum, egg, dairy, or sesame in their facility. Their natural lychee flavouring comes from the fruit, not the nut inside. Their sourced ingredients do not come with priority allergen-free certificates, so they don't label their products as priority allergen free.
I am excited to give this a try in a few weeks. I don't normally try new foods away from home but after all my questions to the manufacturer, I am confident it will be safe.