basically get full set of regular or elite fallen god, and you can get the 50% off for the other set. Or unlock the feat on alts and they get the 50% off from get go without needing to grind a single set.
You don't get the renown, but the feat. So if you got the elite gear on one character, you can purchase the feat on an alt and they can run elite and get the renown and the set on that character will be 50% off. Edit, also, you can buy a second set of elite gear at 50% off. You don't need to regrind the elite renown once maxed.