Killer is faster than Hawkins in CQC. He could match Zoro in CQC combat speed, skills with random scythe while he was using nitoryu, when Hawkins had difficulties to react to Zoro's regular slashes, and even his transformation was overpowered.
Killer with his Punisher blades has much more range and lethality with his sonic scythe allowing him to butcher Hawkins anytime he wants with his superior speed, CQC skills and attack range / power
That's from what we've seen. For goma no sou, it's yet to be seen
As for the survival percentage, I don't think it necessarily has anything to do with Hawkins for starters. All it says is that Killer has a high probability to die during the day, which is the day of the raid. It doesn't say that the probability is due to Hawkins, so Killer can still straight up beat Hawkins before facing whatever would make his survival probability to drop
Secondly, I believe that Hawkins checked the survival percentage of all the rooftop fighters, which is why he claims that he won't side with people who are sure to lose. There is even someone who has 1percent chance of survival who is most likely one of them, and this arc is build with the potential of overcoming the odds, just like how Luffy had a low percentage chance of survival in MF, but it never dropped to zero, with him ending up surviving
It's a way to show the difference between people who believe in themselves and those who prefer following what cards / predictions tell them to do, to show how willpower can overcome all that. As Hawkins stated himself during the first fight with Kaido, he had no chance of survival unless he surrendered but Kid and Killer were different, fought and survived, with that difference most likely emphasized here once again after getting beaten by Killer imo