It still works. But he sure its similar lvl (or higher) that the legendary. Low lvl abras are no good.
Its 50/50 chance, but on ultra beasts it worked 100% for me so far. Lvl 50 kadabra should be fine.
I recomend getting legendary with right nature and hidden power, since some need it. Then lvl it to 100 and fit its ivs with bottlecaps. (or ask some1 to give you a hacked one)
Also there will be 7.5 gen game 100% with trainers to fix the skills of pokemon.
What it will be, no1 knows, but i hope its not gen 4 remake.
http://bulbapedia.bulbagarden.net/wiki/Generation_IV