1. This depends on how you have set up your scene. If you make it like this:
Scene.Root->MarkerNode->TransformNode->GeoNode then the 3DModel (the geonode) will have a fixed position (which you define by setting the translation component of the transformNode)
When working with markers following Tutorial8, the camera is fixed at 0,0,0
The marker node will have a translation and rotation based on its location relative to the camera
If you want the 3D object relative to the camera then you need to multiply the translation of the marker node by the translation you have placed between the markernode and the geoNode (The TransformNode in my chain above)
2. Try reading the Translation property of the GuitarMarker..If you want rotation then read the Rotation propoerty. You can use these to build a transformation object.