may be a good idea to finish timber to protect from drying and cracking..check with specialist paint suppliers but we used to use a mix of linseed oil and terabine (drying agent) that was very successful to protect old timber without changing the colour too much

It is a tricky detail to resolve, especially where the benchtop abuts the columns and the detail needed. The cleanest solution is to finish the bench short, so that the column is freestanding and independent of the cabinetwork and benchtop with about 100mm clearance. This then gives you the flexibility to use a slimmer, more elegant columns, such as a visually simple steel pipe/tube column similar to the one in this photo. Best of luck Dr Retro of Dr Retro House Calls and Dr Retro Virtual Visits

Try any of these. You have dark window frames and they look good against the brick. I would prefer for a solar passive solution for you to have Colorbond shale grey or similar for your roof tiles. And the trim everywhere else in Dulux Ticking. But it depends where you live in Australia to whether you have extensive days of hot sun.

If you do not need insulation installed for the room if you install plasterboard, it would be a lot more cost effective to paint the timber ceiling white, it will lighten the ceiling and give an interesting texture. As per the photos that @Julie Herbert has posted. Plaster board will just be a flat service with no interest. Personal preference...