The fact that you think he would run through them is loughable.
Colby has Hendricks level wrestling, so GSP most likely wouldn’t be able to take him down. GSP has a great jab, but he has never faced anyone with the pace and pressure of Colby. He might win a round or two, but would most likely succumb to Colby’s pressure.
GSP is a wet blanket in BJJ, he doesn’t have submissions. Burns is on another planet in terms of BJJ. Burns could submit him from anywhere. If it keeps standing, Burns could definitely knock him out. GSP would have to run from him with a jab for 5 rounds, cause he has no power in his punches to finish Burns.
GSP looked as great striker against wrestlers and like a great wrestler against strikers. He arguably lost to the first guy who could do both ( Hendricks). Colby and Burns can do both and would be a huge problem for GSP