A nice collection of issues, although I'd disagree a bit with some of the solutions, particularly around prefixing. You first need to check if you have an absolute path and it doesn't work with input that isn't a path. So for me it seems best to focus on -- as the primary measure and prefixing as an additional measure if possible when needing to be extra careful. Most software uses some getopt variant so it should be quite rare that -- doesn't work.

One nice thing about bash is the ${var@Q} syntax that is great for printing stuff and deals with the potential for stuff that affects the terminal in a much nicer way than piping through tr. IMO, it should always be used for pathnames so that you can always just copy and paste the output, which I do quite a bit. I wish it was in POSIX.