Answer 1: Yes but they're not exactly analogous and I don't see them merging. Yarn is a complete rewrite, and the compatibility "surface area" is much lower than Node itself so there's not much pressure for them to merge. Yarn has been working essentially flawlessly for me, so npm-cli is really going to have to surpass yarn in some way for me to switch back.

Answer 2: I don't use global packages often. For binaries I generally add a "scripts" entry to package.json for common tasks, which automatically adds "./node_modules/.bin" to the PATH. For one-off tasks I just run "./node_modules/.bin/executable"