Offsetting a 2D symbol from the 3D object that I've created?

This can be fixed but will require some GDL coding. Depending on just how you made the symbols it could be as easy as adding a couple of parameters to the part to define and x distance and y distance. Then at the top of the 2D script you would add the command

ADD2 xdist, ydist

However, there are a number of ways the parts could have been created that can affect this. If you selected 2D line work in plan and then saved it as an object, then there is likely a multiplier (MUL2) at the top of the script which could affect how the part moves with input distances in your new parameters. Alternately if the 2D line work is used as a fragment, you might not have any 2D script. In that case you would need to add the MUL2 command as described above as well as a FRAGMENT2 command to call the fragment in the script.

If you have troubles using the ADD2 you could post a part and someone can adjust it for you. Then you can use this as a guide for the rest of the parts.

HTH