I am trying to properly understand what aspect of the Atacama question is causing concern.
It seems to be that rather than two competing hypotheses (i.e. X is true versus X is not true), there are many (i.e. X1 is true, X2 is true, X3 is true, or none are true.).
Yes, this is fine.
There should be notable claims for all bar one of the competing claims (where the exception is the (hopefully most prosaic) variant claim that the OP believes, if there is one.)
In the example Atacama question, all of these options are listed as possibilities in the two given references.