You can roll up the cable in the box, and if that is not short enough, you can shorten it. It is a normal power cable with woven insulation around it.

You'd better make sure that this doesn't lead to a loss of warranty... If you tamper with the electronics yourself, you could also be taken to task by the insurance company...

Yes.

*roof

Enter "Eglo Vintage Carlton 2" in Google, go to the manufacturer's page and lo and behold: Height: 1100 mm Ø: 455 mm Net weight: 1,38 kg

Yes, I think they were included. There is a bleaching profile that is screwed to the ceiling. You can then mount the plinth on the side with 2 screws.

I don't really know. The cable is sheathed in textile. It would be a shame to replace it with another one, unless it's the same or similar. Besides, you have to be an experienced electrician to replace the cable with a longer one. I will have to send the lamp back for this reason (what you describe). It doesn't work for us.

Product dimensions: Width 45.50 cm Shade width 45.50 cm Height 110 cm Weight 1.40 kg

Was also already asked, just look at all the questions already asked ;) https://www.galaxus.ch/de/s14/QuestionAndAnswer/wie-gross-ist-lampe-und-wie-lang-ist-das-kabel-11535?referrerProductId=3528439