Note that I do not ascribe to the idea that spacetime is literally "empty" or "nothing but degrees of freedom".
I contend that it is the other way around, we are composed of deformations in the very fabric of spacetime, knots.
Currently with my threaded mesh spacetime model, coupled to the topological interactions which have been shown (thanks to Dr. Schiller) to be viable descriptions of the forces, I've arrived at some interesting ideas.
A neutrino would be a specific type of distortion along the threads, like the pulse sent down a tapped guitar string, not very energetic, but as it is capable of producing interaction of any sort, it by definition has mass.
The question is if they have rest mass, I haven't seriously worked on this issue yet, though it has piqued my curiosity now, but an important thing to remember is the flavor changing only requires non-zero rest masses if the standard model proves correct.
I don't think a neutrino would exist if it stopped moving, as it should just be an excitation across spacetime, very much like a photon.
The difference is that a photon would be an excitation with a twist, carrying not just motion along it's path, but directional influence across that path.
If a photon stopped moving, again, I don't think it would BE a photon any longer.
Absorption and Emission, and ultracold states which "slow" photons or "stop" them are not what I mean by this though.
I mean if you think about a photon rippling along, and picture that rippling motion coming to a stop, there wouldn't be an object there. The wave-particle duality doesn't require there be physically irreducible components to anything, it just requires the behavior to correspond to observations in the right scenarios.
"Every Tom, Dick, and Harry these days thinks they know what a photon is, but they're wrong." ~Einstein