Hi, Bonnie Rae. Welcome to DC.
My opinion is that 99 times out of 100, salted vs. unsalted doesn't matter. If the recipe specifies unsalted butter, use that. If the recipe also calls for salt, you could use salted butter and reduce the salt in the recipe.
Generally, when recipes call for brown sugar, I'd use light brown unless the recipe specified dark.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan