Down vote if you will, I don't mind.

If you had posted a video of you playing this you would be getting much more feedback from people. No matter the level of difficulty, don't expect to have someone take time out of their career/students/practice, do the work, record it, and send it to you, just so you can learn by ear. Everyone has been in your situation. Worst case scenario? You play a not so great audition and your still in the group because it's just chair placement. Best case? Put in the work and really develop your skills and get whatever chair you get. Worst WORST case? You learn this stuff mainly from the work of others, get a high chair, are given parts WAY out of your league for the semester/year and are overly challenged instead of appropriately challenged.

As for the work to do: So you know the snare. Great.

If you can read rhythm (which we will assume yes because you've gotten through the snare etude, and its fairly stock rhythms for middle school or High school), can read notes on a treble clef and know where they are the instrument you should be fine as long as you sit down and put the work in. If you don't know your treble clef, just Google it. There are a bazillion pictures you can reference.

Timpani. Again, pretty straightforward. I think one was 6/8? If that confuses you just break it down note by note and write in where each dotted quarter note pulse would lie in the measure and relate the rhythm back to that. As for the drums, both are 2 drum etudes. One low, one High. If you don't have access to timps, get two pillows out spaced apart and work that coordination.

Directors/judges for middle/high school listen for overall preparedness, good sound quality, correct timp tuning, tempo maintenance, etc. Double check everything whole learning it and make sure it's correct. If you really need help ask your private instructor. If you don't have one, ask a director or seek a private instructor who can work with you one on one.