Adafruit wearable LEDs

My wife has a ball gown with a train:

It has 11 clusters of crystals, which she would like to have lit. I have bought some of the fantastic Adafruit wearable LEDs. Two questions:

  1. Can I wire them in series? This will ensure that I can wire them with the conductive thread without having to insulate it and no worries about it shorting out.

  2. If I use a 3.7V 600 mAh Li-Po to power it, how long can I expect it to last? I have tried using the manufacturer’s data sheet, but it seems to show that each LED will draw 40mA at 3.7V!

Any help would be greatly appreciated!