In #3, Floyd Lawton's (Deadshot's) newfound daughter asks him for a lullaby. She requests the Raffi classic, Baby Beluga. If you aren't familiar with this song, ask someone in their 20s for the first thing they think of when hearing the word 'beluga.' It'll probably be this song.
And the NIH site I linked to above has this neat factoid: "Despite these wonderful lyrics, baby beluga whales are not really white." Heh.
Unfortunately, Floyd isn't versed in the Raffi songbook, so he sings her a lullaby that his grandmother used. The song is An Irish Lullaby (Too-Ra-Loo-Ra-Loo-Ral), and the linked site has both lyrics and a Midi file of the tune. (Note: The Midi begins with one pass of the refrain, and then goes back and starts the first verse.)
I'm rather fond of folk tunes and Irish folk tunes, but I hadn't heard this one before. My mom knew it, though. It's a nice song.
And on the subject of Deadshot, there are a few guest-stars in the last issue of the mini. Chances are, you didn't recognize them; that's because they're wonderfully obscure. This page will explain who most of them are.
On the other hand, if you are familiar with these fellows, then you might have wondered "Isn't s/he dead?" Well, author Christos Gage himself has the answer for you, as well as where each character was last seen. You can find his answers here and here.