Very interesting.

I would be inclined to go with an unobtrusive light since it's the living room and anything too dramatic or a hanging pendant may interfere with your peripheral vision (or otherwise be an annoyance) when you're watching TV, etc. Also, being so near the sliding door, the wind may cause a hanging pendant to swing quite a bit which will cause the lighting to be constantly shifting and changing which I would personally find annoying. I'd go with something simple and subtle, but look at getting a tall standing lamp for the corner near the sofa (or possibly at the other end of the floating TV cabinet). In terms of warming up the apartment, I think you need something on the bare walls. A smaller picture above the floating TV cabinet will help to take the focus off your TV. A larger art work behind the sofa will also help to add some colour and personality, especially if it picks up some hues from your sofa. If you don't like the little Buddha statue, I would look at adding one or two other items that you do like (perhaps picking up colours from the wall art) and making a little vignette. A couple of colourful cushions and a storage solution for the wires, games console, etc on the floor would also help to bring everything together. Something as simple as a woven basket under the floating TV cabinet might help to keep the games console, etc in place unless it is in use.

I actually really like the festoon lights! Fairy lights remind me too much of Christmas to have as an all year round feature.

Pendant light choice would usually be for a specific purpose so if you will move things around I would have a rethink. It may be possible to have a pendant with a long lead & hooks for the cord that would allow you to move it within a reasonable distance of the connection point. Maybe some general lighting might work better e.g. or two or three directional spotlights along edges or the ridge line & on dimmers if possible. Subtle strip lighting at the top of the grey wall & the addition of a feature decorative wall hanging & potted plants would look nice too.