Yep it is Grey Leaf Spot, a very common disease up here in Cheeseland.
And the other is a slime mold.
I would be more concerned about the leaf spot then the slime mold as slime molds co-exist with the grass, and do not actually feed off the plants
, like other fungi do.
As far as going "organic" There is no real organic fungicide, but there is one that may not be all that bad. It is called Mankozeb, its active ingredients are basically zinc and manganese. Follow the directions on the label, and be careful while this stuff is pretty safe it is still an eye irritant.