as the state of the art or business has evolved, so have the terms...
Reynolds, you are correct...PBN is an umbrella of sorts, RNP cannot be stand alone, and many parameters can be of use, without full RNP, hence the transition to a more comprehensive term PBN, but at this point still the same term for the same thing.
Within a relatively short timeframe, both RNP and PBN will be obsolete as well...likely before any of the parameters have been utilized...
probably TBM or some other term...
I design RNP transitions to a GBAS final, which doesnt fit in any of the terms, but I dont care what its called...
its all the same for procedure design, and operators, no matter what the regulators want to call it...