Out of curiosity, why not? Imu came here to force the Giants to become his slave soldiers for the coming war. Even if they DO get enslaved, that would ultimately get resolved when the WG loses. It would basically just amount to the Giants being a larger scale version of the Pacifista on Egghead (where they changed sides multiple times).
Not saying it WILL happen, but there's really no reason it couldn't. I would actually be genuinely surprised if the WG walks away from this arc with NO Giants under their control (even if he doesn't just outright win and take control of Elbaf). I figure it will probably be like Egghead, where several factions walked away with something (Devon and Bonney both having control over the Pacifista for example, not just the WG. But the WG also walked away with the means to power their Death Star and a Vegapunk who is fully on their side.).