How about warm yellow? I think it will go together with bricks and would be a good contrast to dark floor and black cooker. Yellow is an optimistic and cheerful colour and often is associated with food. /Marcin

You should install the WC pan first, and then cut the tiles around it. Depending on how thick the tiles are, you might need to install a packing sheet of moisture resistant MDF or similar so that the WC lid stays up - just make sure the sheet is small enough to be hidden behind the pan. Good luck!

I don’t think they’re quite as chunky as the pea rugs, but Alternative Flooring have a wool carpet range called Pebble and Crucial Trading have a chunky wool range called Alaska. Both are good brands and widely available.

If you must, only one wall. If doing two walls you should do all four walls. Two walls doesn't make sense and just looks like a half-done job. To make it a proper feature rather than a randomly wallpapered wall, it should be the wall behind the bed, so I'd finalise the bed position and then do the appropriate wall. If you do the 3m wall and keep the bed on the 4m wall, it'll look like you wallpapered and then realised the bed was better on the other wall i.e. it will look wrong - unless that wall then becomes a different purpose which makes sense (like aforementioned study for example).