Chromium can use Chrome's flash. Unfortunately, it's not distributed separately from Chrome. This is how Arch LInux pulls it out: https://aur.archlinux.org/packages/ch/chromium-pepper-flash/...

On Debian and Ubuntu, you can install the "pepperflashplugin-nonfree" package to download a copy of Chrome and extract the PPAPI Flash plugin therein and install it.

http://packages.ubuntu.com/pepperflashplugin-nonfree https://tracker.debian.org/pkg/pepperflashplugin-nonfree

Since Chrome is just a repackaged Chromium, you can copy all the libraries from the Chrome download. Including both flash and libpdf.

Yes you can, I do it on gentoo.