Hi Dan,
I don't have much to add, but understand the effort... I am working on a FC de Cuzco de Santa Anna, aka the Machu Picchu railroad roster and history... I am working based on photos both mine and others, as well as builders lists (Robert Lehmuth has some wonderful rosters... the best available) along with various British publications and with significant help from Google Chrome and its translation feature..
I have Plymouth and Porter builder's lists, and have later GE coming...
By default, I am working on all Peruvian railroads (ignoring those silly standard gauge lines) and find that on occasion boots on the ground is not to be under estimated... Try looking at tourist photos as well as some of the places locomotives were purchased (as a narrow gauge operator, some OR&L locomotives as well as some from plantations migrated to central America... )
Good luck
Randy