I suggest you ring the Feast Watson support line and ask them and let them know what type of wood it is, eg solid or veneer and what type. I had such a difficult time deciding what to use on my wood benchtops in the kitchen, the product I used is perfect. I consider aftercare a big factor and the product support person helped me decide because of the ease of maintenance re accidental scratches etc.

all heaters and stoves should have very specific installation instructions including distance above the stove to any mantlepiece and i suggest you start with advice from local suppliers and then confirm with specific written instructions from each manufacturer that you can usually find on line...There are a number of heaters that have wood fires that are designed to be inbuilt in a purpose made wooden frame so hopefully this can be done inside your opening

I really like the pic that LesleyH posted. The wooden rail will be 'warmer' to the touch too, show less dirt and tie is with the stairs beautifully.....I thin it will 'ground' the whole look because, if I remember rightly, the stairs and front door are the only wooden features and the rest is a lot of very modern light grey/white/shiny features. I think another touch of warmth in the wood will be beautiful.

They might be Baltic Pine? What is the age of the house? You could do a google image search for "Baltic pine floorboards" and "cypress pine floorboards" see what the grain and knots look like- do either match with your boards? Yes, you can make them look more like the white washed photo. We have cypress pine boards and recently had them sanded and refinished with Bona White as we wanted to ensure they had no yellowy or orange tinge and make them look more contemporary. They were very orange from the original oil based varnish. We're very happy with them, although we only had one coat of white and it may not have shown up as well as our sample boards. Two coats would have made them more white. The Bona White system was chosen because it is low VOC water based, so doesn't have a strong odour, compared with solvents. Sample boards, showing two coats of Bona White top section, one coat of Bona White bottom section and a varnished board with no stain. This is on Cypress floorboards.