A few things come by default on Arch. See the list at https://archlinux.org/packages/core/any/base/ (many some of these entries like coreutils expand to more packages).
Yes, evince is in the official repos. Just like Chromium and Firefox. Or bash, but not any other shell (as far as I can tell).
This doesn't make sense; nothing comes "by default" on Arch, but evince is in the official repos as far as I see.