9.G:
ZIGGY 4 ARR for Ontario would probably be the one filed for coming from NW as indicated on the airdrome chart for El Monte. It brings you all the way around to PDZ. Not sure whether this has got anything to do with with the LAX airspace structure.
As a practical matter, coming from any distance you would usually get that or the other STAR. They indeed add flight path miles (at least arriving from the NW to avoid LAX inbounds. But, V197 can avoid LAX inbounds, albeit with more handling by the Ontario area SoCal folks. And, if KONT is busy then V197 conflicts with the Pomona SID. But, KONT is often not busy, especially these days.
But, it is possible to get PMD V197 POM under some traffic conditions.
The circumstances do make a good hypothetical. Before those STARS came into being, coming from the NW, V197 if filed was usually granted with a crossing restriction at POM then a heading for vectors to final west of POM.