I can help you with some of the ions
Cl- : the purpose of this is to alter neuron responsiveness to stimulation; also main component of stomach acid which is important in digestion; shift in erythrocytes
PO43- : forms Ca3(PO4) with Calcium which is important in hardening of bone and teeth; an important component of phospholipids; also a component of nucleotides; the most common intracellular anion; intracellular buffer
