Those are House Yu's, they are different, more cockroach like, remember that house yu's lays tons of eggs, while this minikkuris are said to have a weak reproductive capacity (probably 2 babies as much like the pic shows.)
Usually - Minikkuri: factory made, as commercial product - House Yu: 1) adaptation of normal yukkuri to hide in human house. 2) escaping minikkuri that adapts to the environment (maybe including the reproductive capability).
JusticeItEasy said: while this minikkuris are said to have a weak reproductive capacity (probably 2 babies as much like the pic shows.)
Ayazou's mini Reimu, I'm looking at you.
While this is breaking the 4th wall, IMO the two children idea is more about to have one of each types like their parents. Much like parents who want two kids, one boy and one girl (to make things complete and can toy with their children of each genders). It also make it easier to know who the parent who's not present