Before I install Arch on bare metal...few questions

[Linux for blind general discussion]

So, as it says. I very much like my Arch VM.

And I've done a ton of installs on a qemu VM, though I'm now thinking of 
switching to bare metalso I can tweak my system how I want.


So....before I do this.

1. I'm worried something'll go wrong in the archinstall script, or the 
manual install and nuke my (currently working) system


2. Will my USB headphones be connected out of the box or not? On a VM 
they are but that doesn't mean a thing when it comes to bare metal


3. I have two machines, one's /dev/sda, which I'm assuming will likely 
install fine, hopefully


THe other, a laptop, is /dev/nvme, which is what I'm worried about. 
Anything special I need for Arch to install on an NVME?


4. Can I with two HDD, /dev/sda (my current Solus system)wor and 
/dev/sdb (a 2.7T drive), install Arch on /dev/sdb and pick and choose 
which distro to boot? I remember  way to do a console command to reboot 
and have Grub select which to boot up, but I'm not sure if that's still 
a thing?


5. Was there ever a consensus on how often to do a pacman -Syyu in Arch?