How to survive a 19-day backpacking trip with strangers as a (hopefully) stealth trans man pre-everything. Help!

So the college I'll (17M) be going to offers a 19-day backpacking trip in about a month and a half, which I was very excited for... until I started thinking about all the things that could go wrong while I am trapped in the woods, days out from civilization, with strangers.

I will have no privacy and no bathrooms.

I also haven't decided how open I want to be about being trans. Once I tell people, I can't take it back.

There is also little information available online about the program, and emailing will out me.

Problems:

1. Do dudes piss in the woods together like girls go to the bathroom together? I'm going to buy an STP, but how would I even clean it?
2. I am 5 months into T shots. I'm kind of squeamish around needles, and my parents have always done them for me. I'm concerned about emailing the program leaders to ask if they could do it (two injections total) and about it possibly outing me. Gel isn't an option because I have no privacy or water. It also takes up a lot of room. I don't want to feel shitty because of hormone fluctuation or get my period back.
3. I'm so embarrassed about wearing a swim shirt. I watched a documentary about the camp that a student made, and there were so many shirtless, muscular dudes. I feel like it makes me look like a little kid. Tape irritates my skin really badly.
4. Is it okay for me to wear a binder all the time for 19 days? I will be sharing a tent and have a small chest, but I don't want to take any chances and have someone see. I wear my binder for like 10-12 hours a day and never have any pain or feel sore. The thought of wearing a sports bra makes me feel dysphoric. If I were going to wear a sports bra, it would have to be seamless so it couldn't be seen through my shirts.
5. We are flying there as a group, and my passport picture, name, and gender are pre-transition. I'm anxious about going through TSA or people seeing it. I will probably have my driver's license updated by then, but I might not.
6. What if I don't pass for some reason or get outed and they are transphobic? How should I even handle that? I'll be stuck with them.