It's a tough call.
On one side, Rayleigh & Gaban have a clear as day parallel with Shiki & Kyo... Let's not forget both Shiki & Kyo want Shakky too, so there's a realistic reason for those 2 to come in and try to take away Shakky.
On the other side, Shakky is the main prize and Garling is, to this day, the Champion of God Valley. Even in latest chapter (1161) Sommers and people around the island emphasized a lot the fact that the one bound to get Shakky is Garling.
Now, imo, it really depends on what Garling decides to do, because there are 3 paths in front of him:
- He goes for Shakky, in which case he would inevitably face Rayleigh. If this is the case I can't see Rayleigh making it on his own. Shakky would need to be passed to the other Roger Pirates so to be brought to their ship. Rayleigh could buy them some time but in terms of strenght Garling would for sure come out of it as the strongest. Hell, he might even incapacitate Rayleigh and get past him. But thanks to Rayleigh efforts he would not be able to reach Shakky in time (so Ray would still be succesful in his objective of saving Shakky).
- He goes for the main fight (Xebec/Roger/Garp) and actually plays a pivotal role in it. For example, I can see Garling using Eris & Teach as hostages to stop Xebec resisting and use the situation to kill him (in front of Eris & Teach) or to help Imu do something (like Domi Reverse Xebec).
- He goes after Shanks. This is the least likely imo, and the one I can't imagine a scenario for.
Overall, I don't feel like betting on any of these scenarios so far. The only thing I'm sure about is that IF Garling & Rayleigh actually fight, then Garling will come out on top (combat-wise) but Rayleigh will succeed in saving Shakky (objective-wise).
