Like the previous comments it depends on use and the design of the light fitting itself. Also if the light has a narrow beam it may need to sit higher to throw a wider beam to light up the area you need lit up. Generally you would put it above eye level so that it doesn't obscure your view when standing. More often than not it is just a matter of where you think it looks best, most pendant lights have good adjustment so before its installed have the electrician hold it up for you at different heights and see what looks best.

Yes definitely consider your furniture placement. Your lights should connect to the rest of the rooms decor. That is over the coffee table or over side tables. A cluster might work if you vary heights and consider some changes in size and shape of each light. See some examples below. Your light choice is lovely. It will however throw that pattern all around the room, something to think about if it's to be your only light source. You say there will be a fan as well. This will make the pendants move, another point to consider.

Couple of things to consider..... 1. With any lights above a stainless steel sink, the reflection appears on the ceiling, I don’t like it so I installed a black sink. I added very minimal pendant lights, basically they are spotlights on a stick but they can be dimmed. Also I placed mine off centre. Saying that, spotlights can also be dimmed and sometimes, less is more. 2.Pendants in the bedroom can be quite tricky.. Example...they have to be the perfect height, width and as far as a reading light, they’re not adjustable. They cost more as they need to be installed. If you don’t like them, you need to get an electrician to change them. I originally wanted pendants but opted for lamps, happy I did as my bed couldn’t quite be centred so it would have been a mistake. Good luck, hope this helps.

What a wonderful space. I love it. what direction do you come from when you enter the room, that may be the main sightline to consider when choosing the colour, as you want the lights to be sufficiently visible against the background that is relevant from the entry point to the space.