I think you lost something here. Particles are particles — they are not little irreps flying through space. I mean this non-sarcastically: spin-0 particles aren’t scalars flying through space. They are things, the state of which can be described by a function mapping a position to a complex scalar. Similarly, the Dirac equation involves states, and those states involve spinors, but it seems rather odd to say that a particle is a spinor.
(In quantum information, one regularly ignores space: there is a finite set of particles, there is time that is often treated as occurring in discrete steps (just like a computer kind of works in discrete clock cycles), and the particles have states that are, if you squint really hard, complex 2-vectors. (Or spinors! But we’re ignoring space entirely, so there are no rotations, so the transformation laws are irrelevant.) But you have to be squinting pretty hard: the state of the quantum computer is not a pile of 2-vectors or of spinors — it’s more like a map from the set of possible strings of bits, one per particle, to a complex scalar amplitude.)