The torsos are a separate part and quite compatible. The actual box is a treasure trove of bits but failing that you could scour eBay for skaven night runner and goblin torsos to make up the difference.
Not any more they don’t. Thanks, Oxy! They’ll need a teeny bit of work because the head connection format on the old gobbos is torso-male to head-female whereas these are more modern. But I can manage that with sprue goo and concealed putty.
I’ve sculpted my own out of greenstuff. They look terrible up close, but with arms and head attached, at tabletop distance you really don’t notice at all. A torso is such a very basic shape, it’s hard to get it too wrong, and with proper body parts attached you don’t see much of it anyway.