International student in Saint Petersburg: work opportunities, opening a bank account, safety, etc

Hello, I finally decided to go to Saint Petersburg, Russia to study. I already issued the student visa. It was pretty easy to issue the Russian student visa. Can't be more excited. I will arrive the 20th of October. I have bought the tickets today! What about interest rates in Russia? What is the interest rate per month? I would arrive next month with 4000-4700 euros. And later I would be receiving 1200 EUR per month to live. I know it is quite a good amount to be a student, but I wanna work to have extra money and not depend on my parents. I wanna be more independent. I am 19 years old. I am not a kid anymore. Do Russians trust their currency? The currency exchange rate is always around 30 RUB per USD, which is not bad and has been stable during last year. I wonder if it would be better to save my money in EUR and exchange them in RUB or save my money in RUB. I will be living in Russia and I must pay everything in RUB. I will first learn Russian language in the university (even though the university offers English courses, it is mandatory to learn Russian because you are living there). But it is okay, I want to study Languages. Russia has great relations with my country of origin and that would boost my work opportunities once I come back after finishing my studies here. The economy of Russia is growing pretty fast. I would like to find a job in Saint Petersburg and the university told me students were allowed to work in Russia and I would need a work permit. But I think it would take, at least, six months to be fluent in Russian. Maybe four. Can I find work opportunities speaking English, Spanish and German? I am already fluent speaking those three. I want to work to make some extra money. I am only 19, but I wanna start working to gain work experience while being very young. But I wonder if it is mandatory to speak Russian to work in the country, even in language schools. I have considered to find a job in a Spanish speaking school, which is my Native Language and I have given Spanish lessons before. Besides, what is really happening towards LGBT people in Russia? Some people have said there will be an Holocaust against gay people in Russia. I found those news to be somewhat exaggerated. I was in Saint Petersburg last year and I found them to be somewhat accepting towards gay people, as long as they are not so open in public. I was raised in a Catholic family in Latin America and I am used to it. I think Russia looks so homophobic only in comparison to some European countries, especially being that close to Finland and Norway, which are by far more tolerant towards LGBT people. What I am really afraid of is... RUSSIAN WINTER. But I think it would not be that bad. If not, there were not more than 150,000,000 living in that country. I was in Russia last year during summer and autumn. Autumn was pleasant, but very windy. I have already lived in Saint Petersburg as a tourist (1 month and half), but not as a student. The circumstances are different now, by far. As a student, I will be living there for a longer period and have to go deeper into the local culture to understand it. As a tourist, you do not really need to do that. Finally, I appreciate you have taken your time to read this to give me any tips you consider important during my stay in Russia. Thank you in advance. Saludos desde Latinoamérica.