2. AFAIK Go can both compile and load DLLs now. A language that doesn't have native compilation facilities (Java, JS, python, etc) would have to have extra tooling that loads the runtime and program from a DLL. A quick google search tells me Java has this tooling already. I'm sure other languages would too.
3 a,b. See point 1.
4. Yeah, that's fair, although I'd probably still rather have a single process.
6. Also a good point. Might be a useful paradigm for large codebases. Although at that point the usage pattern is so different that the calculus for choosing the architecture is different, and I stand by my choice. Google can afford to build fancy shit for themselves.