3D component models are optional and are not stored directly in the footprint file but as a reference to an external model file via footprint attributes. At the moment the best option with pcb-rnd is OpenSCAD.
Since any 3D model use requires footprint attributes, the tEDAx footprint format should be avoided and the lihata footprint format used when a 3D model is supplied.
If the footprint is parametric, the joined OpenSCAD script should have all the relevant parameters of the footprint also implemented and the parametric footprint script shall generate the appropriate openscad-param attribute in the footprint to get the 3D model match the footprint.
The 3D model should come with the same use-license and dist-license as the footprint. The OpenSCAD exporter in pcb-rnd typically copies the component model into the output so use-license that would "contaminate" the output (e.g. GPL) should be avoided.