Honestly I’d start with the default config file to see if you like the general workflow and then begin modifying as you see fit.  That’s how I started way back when I first learned i3.

Maybe first replace it’s default swaybar with the more customizable waybar.

Happy sway user here!  Not sure I could ever go back to a floating window manager.   I’m too used to tiling now.

cmus.

I know it satisfies 1, mostly sure it satisfies 2, and looks like 3 was implemented somewhat recently

https://github.com/cmus/cmus/pull/1325

yep, just tested and resume works.