Knowing the identity of the one who contacted them, the only question I have is
WHY didn't Polnareff just contact Jotaro?! They were specifically tracking down the arrows, why couldn't he go "Hey Jotaro, so I found an arrow, but the guy who has it can erase time, can you The World him please?". Then Jotaro could introduce Polnareff to Josuke, who could've healed him maybe.
Weve already proven crimson king isnt invincible. You need to be able to kill him from a distance and quickly. Thats it. Do something he doesn't expect.