I did my BM in violin performance (hogeschool niveau) in the United States, then I continued to get a MM (hogeschool master) and a MA (university MA level) simultaneously. I did do some undergraduate work in The Netherlands, but it depends on the school you get into whether it's a smooth transition. Not all schools are at the same level. I feel that, in general, schools in The Netherlands are ahead compared to those in the United States.
Since I lived in the United States for nearly 8 years and I'm basically bilingual, I did not study that much for the GRE and did well. Judging your writing on here, The TOEFL will be easy for you. It's just long. Both the GRE and the TOEFL are 4 hour tests. Not all universities require the GRE, but they will require the TOEFL. There's been a trend that admission committees don't really look at GRE scores when making decisions, and that it's merely a requirement the university sets. There's also a math part in the GRE, but they won't look at that score if you're doing Musicology (my math score was really really bad).
The transition to living here was relatively easy, but that can differ from state to state (I'm in California). I lived with a friend, and they helped me throughout the first two years here. Like most Dutch people, my English was good and there were no issues at all. The internet, social media, and skype kept me in touch with the home front. There is a 9-hour time difference, but we make it work.
I should say that if you get into a PhD program, the school will fully fund you. This means that you will not pay for tuition, health insurance, and you will get a stipend to cover all basic living expenses. You do not need to work.
You're welcome to find my on facebook if you send me a private message, and we can connect through there if you want!