Poser Python certainly can do that - try the "Make Art" button which features in several of PhilC's utilities... Ockham has a script called Loader - "Multi-purpose helper to load lots of things at once." Sounds about right.

I haven't tried a dual PP2 load, but your theory about the numbering sounds plausible. LesBentley is offline following a house move; I'm sure he would know if there was an answer to that one.

Just thinking aloud here - a CR2 can load any number of props along with a figure. No ReadScripts are needed. A CR2 is effectively a mini-PZ3, except that it has no provision for lights (although even those might be hacked in). Might it be possible to use a dummy CR2 with nothing in it but prop references? You can only save parented props in a CR2 from within Poser, I think, but you could probably hack out the parenting afterwards if that isn't wanted.