Silk would be interesting, not to mention elegant. As for paints, the Silver Illusion appeals, but it might throw green (not sure). I also agree the Tranquil Retreat is a good one. I'm wondering how big the feature wall is, and what is going on this wall, eg TV, fireplace, large artwork, etc.?

White and cream can work together and it is a great idea to paint all your trim white to freshen and lighten your room. Whether your cream blinds look dirty if you paint the trim white will really depend on the cream tone/shade of your blinds and possibly the material they are made from. Remember the colours will look different of an evening under artificial lights than they do during the day under natural light. We have uPVC white window frames with classic cream architraves. I recently purchased some block out roller blinds and spent hours agonising over whether to match the windows or the trim so I understand your dilemma. I ended up matching the white of the windows because we wanted the blinds to 'disappear' when they are opened. Have attached a pic to show the white windows with classic cream trim fyi....

Frames, I think, are meant to stand out as a feature. Maybe if you could upload some images, we could have more of an input, but I think white frames would look great against the grey.

Oh! Sorry I misunderstood your post. I think it depends on what type of planting you will have along your fence line. I assume it will be a Colorbond fence? I wouldn't introduce Shale grey. Of those two I'd prob stick with Surfmist but then I think greenery looks FABULOUS against Monument fencing. The whole back of my house is Surfmist acrylic render and we have chosen Monument fencing and garden retainer walls/seating around the perimeter of our garden as it provides a background of depth against greenery. I know you don't like Monument though. Houzz does give you a variety of opinions and does make you think outside the square. Good luck with your choice!