Can I use milk instead of the heavy cream?

For some this is a preference, for others it is not. Calling a preference "correct" or not is taking it too far -- ask people before making an assumption about...

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.

No. Powdered milk is dry, and milk is wet. If you add milk to it, it will get soggier.

Yes, it really doesn't matter.

You could, but be extra careful when boiling it, or else it could sour. Fight milk is very feisty.

You can try doing this if you’d like but you really don’t need to add any liquid to make good scrambled eggs. See the recipe above for help in making...

Yes, if you like the flavor of cream cheese. However, you will have to heat the coffee up enough to melt the cheese so that you can properly mix it...

Tape will not last as long as glue, especially a glue made for paper. There's no reason you can't use origami paper, though.

Cornstarch is totally out of the question. Baking powder (or baking soda) can be used but results may vary.