Yes, metabolic acidosis can occur too.
There shouldn't be any limiting reagents in an equilibrium reaction. If you run out of any of the above, you're probably dead. It's probably best to ignore the RBC membrane to understand this material. The ions will move to their required places via transport mechanisms to maintain homeostasis.
BTW CO2 can react with the peptide chain of Hb to also decrease oxygen affinity.
I think that you're making this subject too complicated.
Have I told you that I
you lately, baylormed? Let me know if you don't have a Valentine.
Join in the fun!