Sometimes just changing up the sheen, gloss level works. For example, ceiling flat sheen, trim glossier both in Navajo White.

I'd match the crown molding to the trim. Often for ceiling color, I choose the lightest color on the same color strip as the wall color. BM's historical colors aren't organized that way, but you could probably get them to mix the Shaker Beige with white to get a lighter tint that is still darker than the Navajo white.

I would paint walls and ceiling one color. B.M. Swiss Coffee, a great backdrop for chocolate sofas. Add a rug and the sofa and rug become the focal point, not the walls/ceiling. Add a blue for accent color:

Hi I am looking for some advice on what colour to paint my ceiling. My walls are a light grey (owl grey) and the wainscotting is Benjamin Moore trim white (satin finish). I was thinking of doing the ceiling mouldings the same paint finish and colour as the wainscotting and keeping the ceiling flat white ceiling paint. Would that work?