For what part of the species object are you interested in using the Maxent model? A species object typically contains some combination of presence points, a species name, background points, and a range raster (which can also be thought of as the study area for modeling). If you're using Maxent models in an age-overlap correlation test to calculate niche overlap, typically ENMTools would use those species objects to create the models.
However, I am about halfway through the process of setting that function up to just take a mostly-empty clade object and an externally-calculated overlap matrix. Once that's ready you can create a set of enmtools.species objects that only contain a species name, then pack those into an enmtools.clade object with your tree, and throw that into the enmtools.aoc function with your overlap matrix. Would that work for you?
basically you'd just create some overlap matrix "my.matrix" however you want, and then do:
and then:
my.tree <- load.tree(whatever you need to load your tree)
my.clade <- enmtools.clade(tree = my.tree, species = list(species1 = species1, species2 = species2, species3 = species 3, species4 = species4)
and finally:
my.aoc <- enmtools.aoc(my.clade, nreps = 100, overlap.source = "matrix", overlap.matrix = my.matrix)
So you don't need anything except the species names, the tree, and an overlap matrix. Would that do what you want?