Makes sense it's cheaper for the second dice because they are both tied to the same health pool whereas the non uniques get a new pool of health for each die

I doubt you can have multiple dice with the same name, unless I've missed something amongst the X number of pages about this game...

For two dice in a play scenario pause the video at 12 seconds. 2 Luke dice and 2 Vader dice. That's what the 15/20 on Luke probably is. 15 points to bring 1 Luke die, 20 points to bring 2 Luke dice.

You have a point, altough there are inconsistancies between the video and the articles (starter sets have the same dice, dice apear in different colors, salvage yard's number is different) so i'm wondering how accurate the video actually is.