I use canned coconut milk.

I find that it's best to whip the mixture as best as possible with an electric mixer before freezing to incorporate air and then stir every half hour or so until frozen.

It's just a stabilizer. I was experimenting with it, but I've made it without. I should probably delete it from the recipe.

You can leave those out. It does help to add a stabilizer like xanthan gum, but not required.

It is the same thing, but you need food grade.

Also, googled “vegetable glycerin” near me—comes up as “skin care”—is it the same? OK to use in food??

Glycerin helps keep it scoopable after freezing. You can leave it out. The mixture will just freeze harder and you'll need to let it thaw a bit before trying to scoop it out.