Thanks for the feedback. There's a lot of instruments in the song that I want to keep, but it's proving challenging to give a pan/frequency space to everything...
The vocals in particular I am fighting hardest with to make them crisp and clear. As @Papanate has said the vocal doubling also seems to bury them, maybe frequencies from them are canceling out or something, and maybe the doubled vocal should be mixed significantly differently so as to not compete for sonic space?
Not sure if anyone has any recommendations how to approach cleaning this up...
I wonder if my mixing headphones, which are 10 years old, are losing their quality too...