Is there any difference is placing a question mark before the exclamation mark and placing a question mark after the exclamation mark? More like... the speaker is astonished more or confused more?
Although it's not something you're really "meant" to do, because a sentence needs only one punctuation mark at the end, I do see this used a lot. Therefore, I'd say it comes down to personal preference and writing style and there is no official right way to do it, so do whatever you think feels right.
The problem with this kind of punctuation is that readers are left trying to guess what you mean. The combination of ? and ! is used in chess notation but has specific meanings that are understood by chess players. Like I tell my students, "you can write whatever you want but if you have to explain or justify what you wrote then it is bad writing."
That said, using a question mark followed by exclamation point in my opinion is ok for dialogue because the exclamation point is adding the vocal tone that is present when people speak, and most readers will see the question mark first and understand what is happening, because we are used to seeing sentences followed by question marks. I don't think it works the other way around, and leads to people guessing or running to style books to find out what it means. Who wants to have to dust off their copy of Strunk and White while reading?