los mayores: the elders

Great rendition by compa Eric Schwartz in the great video below, also about land grabs in Colombia.  (Ojo, he also renders Proceso de Comunidades Negras as Black Communities Movement, which I like, see my previous comments about proceso as a term)

despojos: land grabs

I have previously rendered despojo as disposession, but this rendition could have more impact for political purposes if it fits the context. Despojo can actually also mean other kinds of accumulation by dispossession in the midst of war, or war plunder, but at least in the Colombian context it usually refers to some of the massive land grabbing that's been happening there which has made it the number one country for internal displacement.

The term despojo was rendered as displacement in the video below, which I think gets it a bit off, but I highly recommend the video anyways.  It has gorgeous cinematography and starts out with great footage of the peace community of San José.

mass sick-out: baja colectiva

Collins (astounding that they would have a term like this) renders it as baja colectiva por enfermedad como forma de protesta.  It seems to me that baja, in context, implies the por enfermedad part.  Is it not also obvious that if it's being done colectively it's as a protest? Maybe not, but certainly in simultaneous I would just use baja colectiva. 

On a related note, a walk-out could refer to a wild-cat strike, but the term is also used for student walk-outs, for which I would just use huelga.