Jerry's is a weird sizing, but, generally, it's sized small; Mondor kid's is even worse. My miniature DD wore Size 10-12 Jerry's dresses at 8 ... and Size 8 Mondor at 4, yet, is considered to be very small, tiny, dainty ... and vanishes in the school pictures behind the other kids
Chloe runs absolutely true to its measurements, however you do need to measure it properly. It's also, IMHO, sized for skater's butt: as most skaters have well-muscled backsides and more muscled thighs, they are a bit baggy on non-skater-butt'ed bodies. The tiny tinies who wear chloe successfully at our rink (including some 4 year olds) are all kids who are quite well-muscled, either thru skating or gymastics or dance ...
Junior UnderArmour works very well for skating, by the way ... and it wears like iron. Plus being quite useful for gym class, etc, as it's normal in length (not long for skates as Chloe is) - so you get multi-purpose wear from it.