My understanding of what happens when using separate drives is that one drive is given priority in the BIOS/UEFI menu and then people just use the device menu when using the secondary drive. Windows really only cares about its own drive with this setup, so the bootloader on the other drive is safe. I’ve never actually done this myself since the only system I dual boot on is my laptop and it only has one drive installed. To answer your second question, I just use my bootloader (GRUB in my case) to select which OS I boot into.

Some people recommend having Linux and Windows on entirely separate drives since Windows doesn’t always like to play nicely with Linux. The only issue I’ve ever had with them on the same drive was the time Windows ate my bootloader when upgrading from Vista to 7. Another thing is that you should install Windows first because it will eat the bootloader (as previously mentioned) if Linux is installed first. I also recommend keeping a flash drive with System Rescue CD installed handy in case you have to repair the bootloader.

Edit: Typo

I wouldn’t recommend Clementine since it’s unmaintained. You might want to consider Strawberry instead, which is an updated fork of Clementine.

That having been said, I actually use Audacious because I like using old WinAmp skins.

My mom was playing Jeopardy on her Alexa and one of the questions was about a state in Mexico. Her boyfriend, who was very drunk, adamantly insists that it’s a trick question because “Mexico doesn’t have states.” It’s literally called the United Mexican States. Two of my aunts are from Mexico. It took like two hours to get him off the subject.

A lot of them work in IT.

I use Strawberry for mine.

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).