I had been hopeful that they would get it, and thought odds were pretty good considering they have gotten all of the series up to this point, but I wasn't sure if things would change considering how much everything with Aniplex shows has changed in the past year or so, and especially with Funimation losing the license to Black Butler.
Season 3 of Black Butler, also known as "Book of Circus", is now fully dubbed and available on the site for subscribers. In order to find where season 3 begins, look under Black Butler and start at episode 38.
The Book of Murder OVA, unfortunately, will not be streaming on the site at all, presumably due to restrictions set on Funimation by Aniplex at the last minute. If you want to see the OVA, you'll have to buy the physical copy.
I was referring to Netflix as that is the main reasoning of this thread season 3 on Netflix i know that season 3 is on here but I only have access to subbed version and would really like to avoid spending more money to watch the dubbed version which is what I have been waiting for
edit: Duh, silly me, that was the first Grell arc. But I just went back and checked episode 18 and there isn't a song before the opening. Are you sure you meant episode 18, "His Butler, Transmitted," from the angel arc?