Columns are considered trim, so yes, paint them the same color. I agree with adding the stone to the area above the existing stone over the grey siding. The dormers are the same style and should also be the same colors. Have Fun!

I agree with what youve said, my only question is then the garage doors are the only thing brown - is that ok?

I think garage doors a lighter brown to match a wood color more, and then the front door could be painted that to. Just make sure the trim around the front door is white. Or the garage door should be white like the trim and the front door could be wood colored. Does that make sense?