Does anyone know of a cool (cheap) way to get adaptive optics in one of these devices?

Adaptive optics and cheap don’t usually go together and I don’t know of any successful amateur attempts. In any case, Hadley’s appeal is that it’s cheap and 3d printed, it’s not a precision instrument that is limited by the atmosphere.

That said, assuming you’re doing planetary photography, you can do speckle imaging by using an astronomy camera to take lots of short-exposure frames and running them through software such as AutoStakkert!4

https://en.wikipedia.org/wiki/Speckle_imaging

The mirror used in hadley telescope is spherical instead of parabolic because it is small enough that the difference don't count much for the desired image quality. An adaptive optic would make no sense in this scenario.