YOUTUBE VERSION:
There are 2 reasons for which I believe Basil Hawkins has allied or will ally with Luffy and Law:
1- His Devil Fruit abilities. Now the main ability of Hawkins is to create straw dummies. These dummies transfer all the damage they receive to one of Hawkins’ underlings. Same goes for any damage to Hawkins. And here his underlings are Kaido’s men. So this means even if he keeps disposing of Kido’s men, nobody will question him because he has already shown them that this is his power. So this way IF he is a double agent, he can keep reducing Kaido’s forces until it is too late for Kaido to realize.
Now, this ability to create straw dummies is unique to Hawkins, I mean Oda could have given so many others this ability, for instance, he could have made Pica create Stone Golems. But since Oda did not do that I am sure Oda has special plans for this power of Hawkins.
The other part of his ability comes from him choosing magic cards and based on the card he has chosen something will happen. Now, this again is perfect for someone who would want to be a double agent. With this ability, he can keep choosing bad cards and instead of helping Kaido, he could be helping the Straw Hat Alliance. And finally, he can blame it on Luffy being so lucky that he chose that card. This way again he can cause keep causing harm to Kaido until it is too late for him to realize. Hawkins already did this once by letting Luffy and Zoro escape.
I mean here you could take that someone is O’Tsuru but he drew a card which allowed someone to help Luffy and Zoro to ESCAPE. Now because of these abilities, Hawkins I believe makes a really good candidate for a double which I doubt Oda would want to give up on.
2- Now the second reason for me believing him to have allied with Straw Hats is this panel right here:
In this panel, there is Law, Luffy, Hodem and Hawkins. Luffy and Holdem are about to fight so their expressions are justified. Law and Hawkins, on the other hand, have worried expressions. Law’s expression is justified somewhat because he is worried that Luffy will blow his cover and alert Kaido and his minions of Law and Luffy being in his territory. But the same could not be said about Hawkins though. Hawkins has a worried expression which does not really make sense. I am pretty sure he does not have so much love to Holdem that he will be annihilated by Luffy. So what is he really worried about? Is he worried that if Kaido finds out that Luffy beating Holdem, Kaidou will be angry at Hawkins? This though plausible does not really seem to be the correct reason.
I think Hawkins is worried because of the same reason as Law. He is worried that Kaido will find out about Luffy and Law being in his territory.
I think Law and Hawkins have already met offscreen and Law has convinced Hawkins to join his party to fight against Kaido. I mean Law has been in Hawkins’ territory for a while now so there is good chance Hawkins could have found Law. This could also explain why Hawkins told Kaido’s underling not to tell the Kaido until he examines what is going on to the missing members personally.
Further, from Hawkins, Luffy and co could get hold of Kidd, Killer, and XDrake and somehow convince them to fight against Kaido. I believe this to be highly possible because I think the fight against Kaido will be Luffy, Law, and Kidd vs Kaido.
Also, I feel that since Kaido appeared in front of him suddenly, Hawkins really did not have a choice but to join Kaidou. So he could actually be looking for a way out. So when Law approached him he would not have been more eager to say yes. So based on these reasons, I think Hawkins will either ally to Luffy or has already allied with Luffy.
Also, it is interesting to note that Hawkins said the chance of Luffy surviving to the end of the month is 19%.
But since Reverie will end in 1 week, this survival which Hawkins is talking about could be something way into the future after the fight against Kaido.
*Theory by Ashura the demon