Silas Merlin

Use "translation symmetry", and at the end "export along Y".

Sorry I find this so late.

Assuming this is in Sculpt room :
In a case like this and to answer most of the questions, I think, use transform tool and look closely at the tool options panel :
click : To center mass
click : To main axis (This will have 3d Coat "guess" what the orientation of the model is.)
Then, in the position fields, you can type 0 for each of the axis to get the model centered on the origin of the scene.
Then, I am afraid you will still need to rotate by hand if the model is not aligned to the grid.
I guess, to check if you did it correctly, you could click on "Reset axis", and "To main axis" one after the other to see if they are both the same.

If you want the object to rest on the ground plane rather than be centered on it, you can right click the volume and do "Snap to ground"

Now, assuming the object is in paint room  :
-Go to retopo room
-Mesh menu : take mesh from paint room
-Go to sculpt room
-Geometry menu : "Retopo mesh > Sculpt mesh"
-select transform tool
-check the box "conform retopo mesh" at top left of screen
(now, do all the steps in the previous section to align the mesh, this will align both the copy in sculpt room and retopo room)
-When you are finished aligning, hide or delete the sculpt copy
-go back to retopo room
-Bake menu : "update paint mesh with retopo"

---
When importing a lowpoly I think it makes more sense to import it in the retopo room first to see if changes need to be made before painting.
Then you can take a copy to sculpt room if needed.
and when you are done you go back to retopo room, and in the bake menu you choose "retopo->Per Pixel (no baking), unless you created a high poly version in sculpt room either by subdividing or by voxelizing and then adding sculpted detail, in which case you would bake with normal map.
If the lowpoly has textures, on the other hand, you would still import it in paint room first, load all the textures except the normal map.
If you don't have a displacement map, import the albedo/diffuse as a displacement map.
After you have done all this, save your work as a .3b file.
Now, in the bake menu, do "take subdivided paint mesh to sculpt room"
The tool will calculate the required resolution to hold all the pixels on vertices. This might be too high, depending on your hardware, but it should work. (if it does not, go back to your saved copy and lower the desired number of vertices when doing the operation)
Now, you have a high poly version of your model in the sculpt room with all the paint information
delete the paint object.
re-import the model in the retopo room.
Now you could align the model as described at the start of this post.
Then you can do al the changes you need to make to the sculpt mesh and retopo mesh before you "bake with normal map" from the retopo room.
 

Here is a thing I would try... a "hack" of sorts I guess. but if it works, since this is a public space.... well, the ability might be removed by the powers that be.

anyway, try this :
Install and open the full version of 3d-Coat.
Create a keyboard shortcut for "auto pick" (hover over the box and press the END key, then your key combination).

Now, close 3d-Coat and open 3d-Coat-print and try the shortcut.

If it does not work, it may mean that 3d-Caot-print and 3d-Coat are not using the same folder in documents. If that is the case, locate the options_hotkeys.xml file in both, and duplicate the entry for the auto pick shortcut from one to the other.

Or, you can skip all of the above and simply insert this in your options_hotkeys.xml fils :
<OneHotKey>
            <ID>AutoPick</ID>
            <Room>Voxels</Room>
            <Code>0</Code>
            <Ctrl>false</Ctrl>
            <Alt>false</Alt>
            <Shift>true</Shift>
            <AllowStack>false</AllowStack>
            <UserDefined>1</UserDefined>
        </OneHotKey>

the shortcut here being SHIFT+0 (that's zero, not the letter o)
PS: I don't know if 3d-Coat-print has a specific room other than "voxels", if so, just remove the word Voxels from the xml above.