I think today, both of those plants could reasonably considered to be EMO. (early morning openers)
The terms nocturnal and diurnal have become somewhat flexible, probably because a lot of daylilies don't fit into their strict definitions. In the past, hybridizers would often use the term "nocturnal" to describe a diurnal flower that began opening overnight, and would be completely open by dawn, although the pistils weren't generally receptive until mid-morning. Then, to indicate that the flower didn't start to deteriorate too early later that afternoon, the term 'extended' (or ext.) would be tacked onto the description. A lot of daylilies were registered as "Noc., ext". These were desirable in cooler climates, where many daylilies had trouble opening properly. At some point, I'm not sure exactly when, the term EMO was coined, and has become more widely used to describe plants with this bloom trait.
I grow one "modern" registration that I believe fits the classic description of nocturnal, and that's Notify Ground Crew. It's about halfway open by late afternoon, almost all the way open by dark, and the pistil is receptive all night. The flower will persist through the morning of the next day, but you can see it's pretty well used up at that point. I think that one of the reasons that it last so long is because it's yellow and the sun doesn't get to it. I put quotes around "modern", because although it was registered in 2000, the parents were registered in 1949 and 1971. Curt was going for tall, with a specific look, and that's how far back he had to go to get that kind of height. This is what makes Notify Ground Crew such a nice landscaping plant; it's tall, and in clump strength it's always showing a cloud of bright color hovering well-above the leaves—and more color than if it were diurnal, because each flower is able to do double-duty. I enjoy that "floating blossoms" look—some of the species, such as H. fulva give that same effect.
