Tony Nemo

In the Sculpt room,  Geometry>Import from Retopo. If the details are minor, you can use any tool (logically in Surface mode) and rebake from the Retopo room. If bigger changes are contemplated with the Move, Pose or Transform tools will show the Mesh and it will snap to the new surface.

Alt-Select the belt volume (to hide the other volumes and in the Retopo room, re-name the active group Ammo Belt. Or you could select the volume in the Sculpt room and right-clk Autopo and when complete, you will see your belt in the Retopo room. Autopo is great for non animated parts but you may prefer to use a manual retopology for the figure. Name your various retopolgy groups as needed and save them to different UV maps where desired.

Principal Voxel tools for "warping" would be the Move tool and the Pose tool. The Pose tool has been compared to the Swiss Army Knife for it's multiple uses.

Go to the directory where the exe is installed and you will find both. 

Pressing "Close" is okay but getting it back means Background>Edit Position instead of a handy right-click on the image for adjustment and hiding the image.

Adjust the "Falloff" at the top of the UI. The default is 0 but 10+% will give a soft transition.

Delete the seams you have circled except the outermost (to preserve the separation of that edge loop) and "Unwrap" your new UV map. The result would have all the components the same color rather than the many colors shown.
 
Actually, you could consolidate a lot of stuff before you Unwrap.

It looks like some points need welding. In Maya or Blender, the points are in the same place but 3DC is snapping some to a straight line. When you Import, select Weld Vertices from the list. 

It looks like some points need welding. In Maya or Blender, the points are in the same place but 3DC is snapping some to a straight line. When you Import, select Weld Vertices from the list. 

You don't need it until your ready to export a displacement map. In voxels, it's a question of resolution (smaller voxels wil express smaller details). When imported to your main app, then you use subd for accurate displacement with the map you created in 3DC.

I managed to repair it with a reopen. No idea what transpired. Reran Autopo with great results and had no difficulty selecting vertices.

If you intend to animate the figure, I recommend manual topology to achieve fewer polygons (think of C4D's lousy viewport response). The normal map will carry all the surface detail and in your case there wont be any obvious edge facets that would only disappear with displacement. If character animation is your thing, practice manual topology.

Ignore Backfaces must be off.

In the Paint room, yes File>Import>Model for PerPixel Painting.  Depth will go on the Normal map. Edit All Layers in External Editor should get your wireframe into a PSD layer but I'm not really familiar with the procedure.

With the Brush tied to the zoom, it retains the same size relative to the object.
 
In the Edit>Preferences, untick "Show Brush Alpha Texture.

Disable 'Symmetry' (S key).

Select Layer Blending and select "Lock Transparency". I think that would do what you want as opacity and transparency are poles of the same gradient.

Those artifacts are temporary and wont survive a screen refresh.

Use the Split tool.

In Retopo room, you can create a new UV map and select, drag and drop all the parts in new map. I would then delete all the old ones and in the paint room, delete any previous objects.

Depth, color and gloss can all be turned off  Look for this icon near the top of your display:
 

 
The blue one on the left is displacement and the right is gloss. The one in the middle is color They can be toggled on and off.

When you have your OBJ imported and want the textures you already created (to modify them for instance), go to the Texture menu on the top bar and import them. You don't need to go through smart materials. When I do this, the image does not always cover the model but when rotated, unpainted areas show up so that one could get to all areas. I don't know what causes this but my objective is to modify my color and normal maps, which I am able to do.

Padding bleeds color into the black. I think you can evan determine it's width. I use it routinely and have never had issues like in your sample.

Short answer, yes. My experience: save the mesh in Retopo and load it for the new figure, use the transform tool and snapping/brushing to fit. If you are going to do a lot of (human) characters, you might want to save heads, hands, etc for later use.

To create the final mesh, use the "Symmetry" tool below the UV tools in the "Commands" section of the left hand tool bar. This will make your mesh ready to "Unwrap".