Yo dawg, I heard you like emulating, so I put an emulator in your emulator so you can emulate while you emulate.

More or less. I think there are some differences between the Q and K based models, but they’re close enough to not require separate ports of Rockbox.

You should look into Rockbox. It’s an open source alternative firmware for a variety of portable media players that adds features such as support for more file formats (and it runs Doom). As for which supported players I’d recommend then maybe a flash modded iPod or an AIGO Eros Q or K (also sold as the HIFI WALKER H2, Surfans F20, or AGPTek H3).

Qmmp can use them too.

In my experience larger packages (in terms of file space requirements) install slower, but download speed is a factor there too.

Cancelling compilation is safe to my knowledge. No changes were made as you stated. Just remember that the downloaded files will probably still be in your cache afterwards, so you may want to remove that with paccache.

You mention “partial installs,” but the actual issue is partial upgrades. A partial upgrade is when you don’t upgrade the entire system, but only one or more packages. A partial install isn’t really a term people use, but could probably refer to installing a package without its dependencies being installed.

The thing you’re looking for is called an Input Method Editor. The only one I’ve ever used on Linux is Fcitx which I really liked. I haven’t used it in a few years though.

This is the homepage for the current version.