I have not studied KK but have heard about it but I do study MT and have Studied Poekoelan Tjminde and Tang Soo do and MT seems to have the most physical training incorporated into the classes, the Poekoelan has hard sparring and does do foot sweeps but It is how you train that makes the difference and many styles teach self defense which is their main focus as opposed to fighting. I think you could adapt all if you adjust the training
I have studied poekoelan, Tang Soo Do , boxing and am currently in Muay Thai and it blends boxing with legs, elbows, knees and they go very well together