Flavor – Non-dairy substitute for cheese on baked potatoes

Check out a site called Food Pairing. They have excellent graphical visualizations of what combines well with given ingredients and also use common flavor profiles to help you determine appropriate substitutions. I think this is pretty close to the "map" you are asking for.

Khymos is a great resource as already mentioned.

Probably not.

Goat cheese is a creamy cheese that melts well and makes a great sauce. Feta, on the other hand, does not melt. It will soften some, but still remain crumbly and chunky. The flavor is significantly different as well; it's much harsher.

You'd be better off with a fromage blanc, but chances are if you can find that in the US you'd be able to get the goat cheese there too. A common and more accessible substitute for goat cheese is cream cheese.