i’d disagree with number one. Yes, some people may know beyond a doubt after 2 weeks that they are in the wrong place. But being unhappy is different. It’s hard to adjust to any new situation and it takes time, and it takes time to get comfortable with new people. I remember one girl in my dorm basically cried on the phone home more than once a week, and she announced not wanting to come back after sukkkos and then chanuka. About 2 weeks after chanuka, she told me how suddenly everyone was more relaxed and comfortable with it so more focused on looking outside themselves, and she LOVED sem and ended up having an amazing year.
And to #5, no that is definitely not always true. Many seminaries (and yeshivos) are in debt themselves and just trying to cover costs.
Other advice: dont go just because everyone else is. Go because you want to.
Come in with a positive attitude.
Work work work on being mevater. Just be flexible, give of yourself more, put others first. As a side benefit, people will respect you and like you. Make the best of all the situations that come up.
Try to make friends with everyone at the beginning, even if it’s hard. Bring a group game and arrange a game close to the beginning of the year. Also a great ice breaker.