Thanks for the great photos! My opinion is that it isn't daylily babies. At that size, I'd expect to see some of the thick roots like what are on adult plants. Even my tiniest of seedlings grown from seed have those roots. They are usually kind of flesh colored and bulbish looking. Know what I'm talking about? I'm sure that there is a technical term for them, but I don't know what that is. They are kind of like a finger, with little roots coming off of them. I don't see anything like that in your pictures.
I'm really not positive that it is Johnson grass, but that is all I could think of. I'm sure that someone else with more knowledge will help though. I could be totally wrong about all of this.
