Black honey? Was it black when you took it out? From the picture it just looks like ordinary honey in dark brood comb. If it was truly dark, then yes, different flowers, buckwheat in the States is the darkest, all depends on your flora.
Did you use foundationless frames? The bees will draw out a bit of drone comb, the ugly bumpy stuff, on most of the combs. There may have been some queen cups on some of the pictures, but I didn't see anything that looked like they were actually in process of making a queen. I find that they often keep a few cups scattered around just in case, or don't fully destroy old ones.
Looks healthy to me, assuming that there was more worker comb in there elsewhere.