just a bit of dna from karin , yuugo etc is not enough to get their powersI mean it metaphorically. Sasuke has all the powerups he needs right infront of him. Naruto just has 1 tailed beast. 1 thats OP but still.
Kabuto is a medical ninja and spend half his life in a lab experimenting , who knows what he had to do for their dna to work with his body