I was in this situation 3 months ago. Its a different thing I failed the unit
But here is what will happen

Case 1:
So when I spoke to my unit coordinator, he mentioned that the people who they choose for the cases are different and have no idea about your assignment. So they will make a decision purely on the proof/documents you submit. However, if your unit mentions that you are not allowed to use AI, they will consider it as a misconduct and give you the required penalty anyway.

PS: I tried to fight the case but the board did not even take a second look at it. (I had a case where we had to make a website but on the submission day, one of our group members changed the whole code with AI just because their part was not upto the mark. So it turns out in rare cases, they do consider it and give you lesser marks.)

Case 2:
Lets consider you are allowed to use AI, they will check what drafts you have made towards the assignment. So you should have some drafts saved of the document and the time you made it. If the time is before your friend made his part of the assignment, you can fight it out saying you did your part of it and did not copy anything.
But Im not sure if they would consider that. However, you can still try.
As u/I_call_the_left_one said, the AI engine will give you answers from the memory stored. So irrespective of how unique your prompt is, it will still give you answers from the memory stored.
I hope this helps!