The lamps cannot be replaced. This was an error that we have been able to rectify in the meantime.

There is neither a ground spike nor a power cable included. The Hue Lucca is intended to be screwed onto a fixed base (wood or stone) (there is no mounting option intended by Hue for a ground spike). So that nothing is confused, since digitec shows the video of Hue Calla, the Hue Lucca is operated with 230V. The Hue Calla Philips Hue Calla Base has a ground spike in the perimeter as well as cables for Hue's 24V system.

According to my research, this should not be a problem

This can be done quite well using three suitable screws and concrete dowels (not included). In any case, the cable must always come from below and be connected in this way. There are no cable grommets on the side of the column. Qualitatively, I can recommend the thing. It works as it should and looks nice and valuable.

It is possible, you can also connect with other Hue systems, but you need to buy the Hue Bridge. Concerning the content, there is only the lamp :).