I tried Ironfox for several weeks some months ago. I like the project, but it was painfully slow, mainly because it disables JIT and some other things. (Brave also has a JIT-less mode, but I found it to be faster than Ironfox.)
Also, it comes with uBlock Origin preinstalled, which is good, but the devs enable by default a ton of lists, which contributes to the slowness. I suppose that if you have a fast device it won't matter, but on a low to mid-range device it becomes unbearable. The best you can do is disable the preinstalled lists and use one of the modes recommended by uBlock.
Same. I've tried dozens of music players, but I always return to mpd, though I use Cantata as my front end. And M.A.L.P. allows me to control playback from my Android devices.
I also quite like QuodLibet, but my computer has a bug where the music randomly pauses when using Gstreamer (which QL uses), so for the most part I use mpd.