Nothing more is known — not yet, anyway — about this interesting family (if they indeed are a family — where is their mother??). What was their act? Trapeze artists? Jugglers? Strong man, with assistants? It's hard to say from their outfits.
I really like the smaller boy's crazy-striped costume, and if you look closely, you'll see that the dapper man (the father?) is wearing a shirt with a rather curious design on the front, which is similar to (but not exactly the same as) the shirt worn by the older boy.
If anyone has any information about these performers, I'm sure you'll let me know.