We are renovating our 70's cedar clad pole house. My husband painted between the ceiling beams in the kitchen/dining/living open space. He has just finished laying parquetry on the floor. We felt it was in keeping with the wood but felt the ceiling needed lightening up. It definitely brightened the place. I love it. I also sprayed some light fittings that were green fake verdigris with white paint. That also updated without detracting from the retro feel. Our kitchen has cupboards painted white and some drawer fronts in a wood finish.

Sounds like you've made a decision not to cover any of the brick. Just to answer your question - the masonry adhesive is applied to the brick surface (not the Gyprock) in blobs approx 450mm apart. It sets pretty hard so to remove it at a later time you'd probably have to chisel it off. Any residue left in the surface of the brick could be touched up with brick coloured paint. Apparently you can also use cornice adhesive. Same way of removing & hydrochloric acid would remove any residue.

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!

I agree with both your painter and your Google result. The issue is something that has soaked into the surface of the old wall, particularly as you had an odd result when cleaning. You can’t expect the painter to sand and paint as part of the original job but they may be able to offer advice and action if you’re prepared to pay them. If you want to DIY I’d be sanding the wall and trying some stain locker undercoat.