Can I use imitation vanilla extract?

You could. First, you may want to take a small sample of it and only put it on a little bit of the perfume, so you can try it out.

Use vanilla extract.

I don't think you should use a cast iron pan but it could work if you are desperate. I would definitely use a gas stove.

Use only one or two drops, depending on how much hot chocolate you're making. Vanilla extract is stronger than some might think, so don't use too much of it.

No. You can definitely omit the vanilla if you like.

Most supermarkets sell it. You can get pure vanilla extract or imitation vanilla extract (which comes in a bigger bottle, and works exactly the same).

Yes, but you may have to alter some of the amounts as you go along if the consistency is wrong.

You may add vanilla extract.