Can you pinpoint the actual question in the title? If I understood correctly, the question is something like:

Is Linux's 3 syscalls, and FreeBSD's and Solaris' sendfile function copying file attributes to the new file?

Right now, it reads to me like nine questions bundled together - one for each call - each of which is best answered by linking the corresponding documentation. This doesn't really make it a coherent, useful question for a Q&A site, IMO. If the underlying idea is to make it possible for people to select a function, on each platform, that copies files with attributes, then it should be presented that way: "how can I copy files with attributes regardless of platform?" - and if there is a platform-agnostic way, that should be an acceptable answer. Unless there's some other overriding factor you want to consider (performance?) which should also be stated explicitly ("what's the fastest way to copy, preserving file attributes, on each platform?").

Karl Knechtel‭ Better now?

Yes, I think that fixes all problems.