Learn English – Hadn’t/haven’t- difference in meaning in the given context

The first example is fine, except you might rephrase it as "I ordered it from Pizza Hut."

In the second example, to does not indicate the source of the pizza. Again, for this example, you would use from since from indicates that the source of the pizza is Pizza Hut. Also, using ordered from does not suggest that you have the pizza in your possession at that moment. You can use it even if you have just placed the order and it's barely going to be made.

You can use to to indicate the destination, as in "I had the pizza delivered to the house." You might get away with ordered instead of delivered, but it seems a little strange in my opinion. I don't advise it.

You should use ordered to when someone is issuing a command. For example, I was ordered to order a pizza. This means that someone instructed you to order a pizza.

The difference between "haven't thought" and "hadn't thought" is that the former speaks about an event that started in the past (probably recently) and is still on-going whereas the latter speaks about an event that ended in the past before a certain other event that happened afterward.