User PowerPyx made some great videos for this that are all 3 linked below. As well, IGN did a more text related guide that also has 2 videos and a map here:
http://www.ign.com/wikis/batman-arkham-knight/Batgirl:_A_Mat... In order to activate the jack in the box, you must approach the item and "use" it. I do not know how to do this on keyboard, but on an xbox controller its "A" and on a playstation controller its "x". Also these, like all other collectables in this game, are not time sensitive. So you can beat the DLC and return to do it.
Jack in the box:#1 - 0:05
#2 - 0:30
#3 - 0:52
#4 - 1:25
#5 - 1:54
Teeth:#1 - 0:05
#2 - 0:30
#3 - 0:51
#4 - 1:16
#5 - 1:38
#6 - 1:57
#7 - 2:16
#8 - 2:39
#9 - 3:02
#10 - 3:23
#11 - 3:41
#12 - 4:00
#13 - 4:20
#14 - 4:37
#15 - 5:00
Balloons:#1 - 0:05
#2 - 0:25
#3 - 0:46
#4 - 0:58
#5 - 1:16
#6 - 1:40
#7 - 2:04
#8 - 2:22
#9 - 2:42
#10 - 3:07
If you have any questions/comments let me know! Good luck and enjoy.