For fixer I use Zonal Pro, but I'm not particular about which fixer I use. I use a hypo eliminator (forget the manufactuer... Sr. moment), and use Photo-Flo, but only because Photo-Flo is readily available locally and I have so much of it. But if I ran out, I'd probably go back to Edwal LFN.
The point about single sourceing is well taken, but I usually just order from a vendor that carries all the items I want/need.