Select multiple overlapping meshes and get back one clean, remeshed low with all of their textures baked down onto it in a single atlas, re-runnably.

It's a volumetric remesh method built on native Blender 5.1 OpenVDB grid nodes that simply don't exist in earlier versions. It can clean up genuinely tangled or overlapping topology that vertex-domain smoothing structurally cannot fix. The add-on's minimum stays at 4.2 - this one method just isn't available until you're on 5.1+.

Those are the two methods that actually fuse overlapping geometry into a single surface. Decimate only reduces existing topology - it can't merge pieces that aren't already one mesh to begin with.

Yes, that's genuinely the target it's built for. A single clean UV map, Unreal-correct FBX axes, and the high-to-low UV transfer are all designed with that pipeline in mind.

4.2 and up, with 5.1+ unlocking the SDF Smooth remesh method.

No, not for scan-to-textured-low - the color bake runs entirely inside Blender, including atlasing multiple pieces together through Merge & Bake. You'd want an external baker if you're after full PBR maps; Finish Stack handles the explode, prep, and export side of that handoff.

Yes - pick Unity in the Export panel's Target Engine selector and the correct axis convention and naming get set automatically.