I have papered with lining paper, then applied emulsion, but brown stains are showing through the emulsion. Can I use stain block on walls that have been papered with lining paper?

Our house is a cottage style built in 1927. It has a green roof with ugly dark green shutters and doors. I am wondering what colors to use to repaint them? The siding is beige which I also plan on changing so would also like some suggestions for the siding