Repair 3 Complex STL Models for 3D Printing — One Watertight Shell Per File

I have three completed sculpture models that need to be repaired and prepared for professional 3D printing. The models do not need redesigning or full retopology. They need mesh cleanup, Boolean union and/or controlled voxel remeshing so that each file becomes one watertight, manifold shell with no holes, inverted normals, bad edges, internal fragments, noise shells, or intersecting geometry. The three files are: an Inferno bowl composition, a hand holding a figure, and an ornamental title plate with lettering. The final dimensions must remain exactly as specified: 154 × 158 × 86.4 mm, 61 × 88.2 × 125 mm, and 50.3 × 61.4 × 44.4 mm. Visible details must be preserved, including the face, glasses, fingers, clothing, Cerberus, Roman numerals, ornament and lettering. Please deliver three repaired STL files and screenshots confirming the final dimensions, manifold condition, and one shell per file. Experience preparing detailed organic sculptures for 3D printing is required.