Just make sure you document the whole change eg. Why you wanted to change, why it wasnt working etc.. what you like about your new choice/ visions or ideas that you may of had. Also maybe flick an email to your teacher even though he/she might not see it because they are your mentor.
Ur pretty much in, you should be very confident about recieving an offer in the main round. Last year it was 97.4 with eas. Im sadlyf I didnt make the cut around that atar.
From what I have seen there arn't any scholarships that are specifically for all rounders or state ranks, however these accolades can definitely be of great benefit if you are submitting a scholarship application in the next few weeks.