I never thought about the statues, they were just there :D. But you made me curios, so I had to do some research. They don’t have anything to do with the place being a market, because all the statues are local folk singer/comedians from the early 20th century. And they say that they match well to the market as this is the place were the common people are meeting, so there are no royals shown but the guys that made people laugh and happy at that time.

And just as a sidenote: We have also a lovely tradition on the Viktualienmarkt, because every year during carnival (always on Shrove Tuesday) the market women are dancing in special costumes. But I have to admit that I only saw them on TV, never in real.