I've done the test and here's result.
The 'seed/loot table' theory is correct. I've gotten 3 eye of etchi, 2 jeram, 3 stolen promise in 15 rifts.
Kadala does NOT follow the game's loot table. I've gotten Chantodo orb and Andy (min lvl=60) in the same lvl34 game which's supposed to load...