Some of them lack Stand animation, which is afaik necessary for models to work. Others have mismatched animations, like Stand being actually Attack or the opposite. Animation sets of some of them needs some curation and proofreading before they can be put to actual use.
Edit: The assets seems be having UVs mirrored by X axis. Didn't try them ingame, only in Retera Model Studio, but it's unlikely that it's RMS flipping them. Can't check ingame atm.