Here's my 2 cents. My background is I studied engineering in the UK where I live, but grew up and lived in the Germanic world. I have a brother and several friends and relatives who studied in the US, and friends who are German graduates. So maybe I can Frankenstein some advice for you.
- In the US, you study a broad range of subjects at undergrad. So my bro had to do literature classes and such, even though he really just wanted to mess with computers. My UK and Germanic (Scandinavian/German/Swiss) friends went straight from high school directly into Engineering and only Engineering courses. Advice for doctors: save time this way. You'll be cutting up carcasses your first week of uni. I've met doctors in their early 20s and nurses in their teens.
- "Being a student" is different in Europe, and it's different between the UK and the continent. In the US, there's a 4-year ideal. You go, you study for 4 years, you're done. Not everyone manages this, but the top end at least is very much aimed at you being able to do that with your life. In Germanic countries it's relatively normal to take time out, even have a baby. Plenty of people take 7 years to do a 5 year course. Many friends of mine have done this. You get stressed, you take a semester out. You have a death in the family, you take time out. You generally find that people try to balance studying with life. This also means you'll find older people at university. 27 year olds are common.
- The UK is similar to the US in this respect. Almost everyone I know did their UK courses in one stretch, in the allotted 3 or 4 years.
- Many European universities have no campus as such. They're just spread out around the town. A small town like Cambridge is maybe the closest you get to a campus university, but it's still got town in it. Oxford is also a bit hard to classify, being in a medium sized town but with the colleges all in one section, with independent businesses and shops thrown in. But being out in town might have a big effect on your social life, so think about it.
- Getting into college is more straightforward in Europe than the US. They look at your grades, and only a little at your work/life experience (secondary ways to get in). In many countries there's a GPA you need that's published each year per course. Assuming you did the right mix of high school courses, you can look up what you could have gotten into.
- In the UK it was just a couple of pages when I did it; a list of your predicted grades, and a half page recommendation from a teacher. For Oxbridge it's then a couple of 30 minute interviews, and an offer letter saying what they need you to actually get on the exams. But you're not going to miss the place if they send you an offer. And you can do 6 applications on the same form.
- Very little special treatment in the European systems. Not a lot of stories of rich kids getting into Oxford because their dad built a library. The most you get is the boat race guys who study something odd sounding, but these days a lot of them study a real subject and do the real homework while training like nutters.
- In the US, it's monstrous. First there's legacy and donation people, and sports scholarships. Those are not open to most mortal folk, and I have zero idea how exactly you wrangle a place that way. So then there's filling out a large form, which costs money. There's SATs which you need, more money, more time. Then you gotta find a bunch of teachers who will write that you're a genius. And then you gotta demonstrate that in an amazing essay. And repeat for each university. I ended up not applying in the US when I got my offer letter in mid December.
- Many, many courses are in English despite being in the Germanic world. They don't like to admit it, but their languages are slowly being invaded by English. Also they understand you need English in modern academia. A fair few higher level science courses will be in English entirely. All the young people will speak English, many of them well enough to write academic papers. Anglo culture is everywhere, people will have watched your TV series and they know your music. Even to the point where several of the top acts in those countries are known for songs sung in English.
- Are the degrees accredited? This is an interesting question. In the UK and US I've never heard of anyone being asked to prove they had some degree. The facility does exist to ask your uni of course, it's just I've never heard of anyone being asked to see their diploma. Now it might matter if you're going to use the degree to get a further degree, but from what I've seen plenty of Europeans show up at Oxford to do a masters or DPhil, no problem. Other way round probably mostly works too.
- The only place I've ever been asked to show my diploma was in Switzerland. I had to go collect it at my old uni.