Whew! After many hours spent adjusting levels, panning, EQ, compression, ADT, and various other things, comparing the results each time to previous versions, and several reference songs, as well as listening on headphones, earphones, and speakers, I've finally got this mix to a stage I'm happy releasing. Many thanks to Nina, as always, for suggesting various things to improve along the way.
This is now a substantially different mix from the original. A lot of minor and subtle tweaks (and a far less subtle effect and set of edits for a certain line in the first verse) all add up to make something that's hopefully a bit more professional sounding. Finally, this song has the mix it deserves.
Thank you for helping to make this possible! I hope you like the result as much as I do.