[golf_sceptic]

While we are hair splitting - are they both equilbrants or is one a resultant?

I'm not familiar with the term "equilbrants", but action/reaction pairs are always equal and opposite, and it is helpful to identify the action/reaction pairs before considering resultant forces on each object.

I would consider equilibrium (taking a guess at your meaning) to apply to an individual object within a system, or to the system as a whole. Action/reaction is a different concept to equilibrium.