For example this question is very specific to OS, editor & viewer inverse search integration. Is this appropriate question for this site? Should this be on superuser instead?
These types of questions are fine for the site. If they don't get asked here, I'm not sure where else they would get answered. This is what the tagging system is intended for. You can easily highlight tools/environments that you are familiar with, and hide stuff you don't want to see. After the site gets up and running fully, I hope that there are more questions than one would want to read. That the sign of a healthy, robust, inclusive community. It also means that your obscure question is more likely to be answered.
I think the criterion for whether these questions are acceptable is whether there is some specifically (La)TeX related content to the question. For example "How do I add a keyboard shortcut for a spellchecker in Emacs" would not be appropriate, even if the documents the OP wants to spell check are .tex files.
But questions like the one you linked to, where TeX is integral to the content of the question should be allowed.