, interesting topic!
It's hard to tell what your top two pictures are, since the flowers on the Poa species look so similar. It might be useful to show pictures of the "ligules" as well.
Those little tassels in the background in the bottom picture look like KBG; the long skinny one in front looks more like fescue.
This picture shows a ligule in general; apparently KBG has a "square" ligule while trivialis is pointy.