Nice puzzle! 59A seemed like a mismatch but I eventually figured out it could be a singular “they” in the clue. One question and one nitpick:
I still don’t quite understand 48D. (Maybe because the idiomatic use is always A HALT.)
I knew what 27D was right away, but the use of “Co.” really threw me off until the very end; as a 501(c)(4) I don’t think it’s really a company in the generally understood sense. Maybe "Org." would be better.