Hi, @Bedonimarz!
Welcome to the TWB! 
Unfortunately, we don’t always receive feedback. There is a lot of topics about that. But I recommend this one.
Yes, other volunteers do the reviewing. And, yes, you can review the tasks completed by our colleagues. Remember that you need to be a verified translator to translate and review some projects.
I’m sorry, but I do not know the answer for that. If you can wait a little longer, someone will answer it. Until then, thank you for your patience.
I think the project manager can choose to disable that function.
I don’t know. It’s better to not have because this can “sounds” like an invasion of privacy. If you want to connect with people, you can try to click on their profile’s photo and then you can check their page on TWB. Try to send me a message for testing purposes.
Same answer of the third question: I don’t know. I just found that one too. If you want some tips on free courses about translation, I can suggest these.
Don’t worry. We’re a community here. If you have any more questions, feel free to ask.
Happy translating! 