The fact that they were able to replicate the original effect (what people thought was flux pinning) that made everyone think it is superconductivity and then conclusively show that it is not superconductivity is pretty strong evidence.

That's exactly what I thought at first. And then I realised that the 'ferromagnetism+diamagnetism' article does not actually provide a mundane explanation of the "half levitation": They estimated that their sample had very strong diamagnetism -- at least the 2nd strongest of any known (non-SC) substance, assuming their sample was pure (but we can be certain it isn't, considering that they just had one tiny flake levitate), so quite likely the strongest. And superconductivity is a possible cause of diamagnetism.

I still think the chance it's a SC is really low, but "conclusively show that it is not superconductivity" is not quite true.

There is no meissner effect, so it is not superconductive. I worked in this field, the paper as described is pretty damning. I think your reasoning is motivated.