Stick with a ceiling white for the ceiling. That with the white trims will give the room longevity as you leave them as is each time you change the wall colour.

It is impossible to say without seeing the unit and understanding the natural light and the other colours. I would check out this link from Dulux, then run down to Bunnings to get some samples. https://www.dulux.com.au/colour/whites-and-neutrals/most-loved.html Dulux Vivid White always works well on 1960's trims and doors, but it would be too clinical for walls. Best of luck, Dr Retro of Dr Retro House Calls

I don’t want to paint the beams I want to paint in between them but as my walls are beamed and the ceiling is vaulted I don’t know whether the whole room has to be painted the same colour or I can paint the ceiling one colour and do the walls in another.

I really like the ceiling, as others said it gives it atmosphere and frames the view. When you say pine, I'm thinking you mean the finest of all the pines - Oregon which is fine grained and a warm honey colour. I have a cathedral ceiling and I would gladly swap my bland white faux Hamptons look with you any day! I would look at a large rug for the floor - if the budget is small, find a carpet that you like and get it edged as a rug - my favourite hack. I agree to bring in some black in the curtain rods and swap out al that cream/yellow paint for a neutral white. Your kitchen reminds me of mine circa 1998. Change the splash back to something neutral. Even white painted glass or a white textured or interestingly shaped tile. Swap out your bar stools for timber and introduce some timber elements in the kitchen to match the roof. Think chopping boards,, timber bowl for fruit, utensil holders, pot plants. Paint the walls white as well. All the creams in the world won't help the ceiling look better. you need to work with it not against it. Good luck and keep us up to date!