Merge STL, Texture & Export

I have two separate .stl meshes that belong together as one character-ready asset. I need them seamlessly merged into a single, watertight model, unwrapped, and dressed with a custom texture.

Once the texture is applied, please export the finished asset to .obj (including the accompanying .mtl and texture maps). Clean topology and proper UVs are essential so the model will deform correctly when rigged later.

Deliverables:
• One combined, manifold .obj with matching .mtl
• All texture maps (base color plus any normals/roughness you create) in lossless format
• A quick viewport screenshot confirming the texture placement

I will provide both source .stl files as soon as we start. Let me know which tool you prefer—Blender, Maya, ZBrush, or similar—so I can stay consistent with my downstream workflow.