in 1) how are version updates written. Is there an open policy on code language & compilation? If so how are they all brought together to make a seamless development standard?
Again, your question is in the context of what you call "FBSD". What do you mean: The kernel, the base OS, or a typical complete installed system, with lots of ports/packages?
For the kernel: AFAIK, the only language in the FreeBSD kernel is C, although some of the code is inspired by OO concepts, so a good knowledge of C++ is advantageous for understanding the code. This is in contrast with Linux, where C++ kernel modules explicitly exist (I've helped write some), and Rust is being allowed into the kernel recently. For the FreeBSD kernel, a style guide exists (I think you find it with "man 9 style"). Those two bits if information are sufficient yo define a policy. For FreeBSD, it sort of doesn't matter, since relatively few people have the commit bit for the kernel, and we can usually assume that they know what they're doing, language and style wise.
For the base system: I think most of the same rules apply, but I'm not sure of the exact style guides for other programming languages (such as sh, which is certainly a relevant component of the base system), nor what other languages are explicitly allowed in the base system for development (I suspect none other than C and C++, given the lack of mandatory compiler / run time support in the base).
For the ports: Free for all, since most code in ports is not controlled by the FreeBSD project.
You are asking "how are version updates written", and the question I answered is "how is the code that goes into updates written", now "how are version updates reviewed, accepted, committed, and distributed".
In 4) above I was rather thinking of the religious analogy where different biblical texts are compared verse by verse, page by page. This has been done by professionals in that area, so it's not really a childish concept.
My point is would it be possible to create a similar parallel comparison between code & say the native tongue of English, one that for newbies addresses the mental divide . It would be revolutionary as a teaching aid if it were workable & worthwhile. What do you think?
The best example of this is literate programming. The extreme case is the source code for TeX (Don Knuth's text formatting system). The source code is written in a programming language that can naturally be printed, and it looks like a book. Calling it "commenting" doesn't even being to do it justice, as the
book explains in fine detail what the code does, why it was written, how its parts relate to each other. To turn the source code into a book, you use a tool called "tangle" or "weave", which converts it automatically into TeX source, and compiles it into book form. You can take exactly the same source code and use the other of the tangle/weave tools, and turn it into a programming language (used to be a dialect of Pascal, today I think it is a very modified dialect of C), which is compiled to create TeX.
Reading the TeX documentation (both as a concise book, sort of like a user's guide, and the actual code) is really an experience. It is one of the two example of the best documentation ever written (the other example is the System 360 Theory of Operations).