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!!!