>>1052098Ironically, the one you just posted is a folding or breakaway frame (see the break in the down/top tube, with the silver handle for tightening that's mostly hidden behind the seat tube?), therefore "not a minivelo" based on your definition.
Pretty much any bike with a single tube spanning the headtube and seattube (instead if separate top and downtubes) is meant to come apart.
For instance,
>>1051868 is also a folder/breakaway frame. See the big plastic handwheel on the back of the seat tube for cranking the parts together?
Pictured: A proper minivelo