1. I would prefer painted wood but you could also go with MDF and save a lot of money. Talk with your builder about options.
2. Did you click the link? If you did, you would have seen a
"species" drop down box. At that point you were instructed to
"Select" Santos Mahogany to see pictures from the Mirage web site.
You will see a picture among others of a white fireplace and white baseboards along with Santos flooring. The white features really bring out the luxury of Santos.
It's all opinions here and you asked for them
Good Luck!!!