I can't actually read the paper, but according to the accompanying article jamesf linked to:

Hoping to firm up such notions, Wissner-Gross teamed up with Cameron Freer of the University of Hawaii at Manoa to propose a “causal path entropy.” This entropy is based not on the internal arrangements accessible to a system at any moment, but on the number of arrangements it could pass through on the way to possible future states.

They are talking about "causal path entropy", a term they defined, not "entropy", the well known physics term. Confusing them would be a bad idea.

Power maximisation and entropy maximisation are closely related concepts

Power maximization is what an intelligent agent does that values power. What you linked to is a statistical tool for finding priors. They are unrelated. Am I misunderstanding something?