I don't know if there are any extra health benefits for eating blue type cheeses over other cheeses, or if eating extra moldy cheese over normal cheese.
I've never thought about intentionally trying to make a mature non-blue cheese into a blue cheese but why not? It does happen naturally some times if the two are close togthere in the fridge. I think your non-blue cheese needs to be fairly moist for the blue Penicillium roqueforti mold to take hold. Plus you'll need to pierce the non-blue cheese, several posts on how in the Blue Cheese Board. One problem is that most non-cheeses don't have the vacancies or gaps inside to get good bluing. Let us know results if you try!