Aight, I'll jump in.
I do use the word "emptiness" loosely to refer to both Fruition and seeing things as they are, and this probably needs some revision. I fall into the same basic trap as the original dudes did with Nirvana, where they used it both to describe Fruition and to describe Arahatship. It is the same basic categorical ambiguity. The relationship between these is an age-old question, and is basically just one of categorization.
As to seeing "emptiness" in real-time, this is what anagamis do particularly well, especially those who have been them for a while, and what is means is that they can notice that sensations are just where they are, doing just what they do, on their own, not observed, not as object, but simply as manifesting transience. This comes as much from having clearly penetrated and understood the sensations that seemed to make up "subject" as it does about anything to do with "object". However, there are still processes that are somewhat artificially dualistic, distorted, subject-objecty, or however you want to put it.
As to primordial awareness, it actually becomes something of an extraneous concept at the end, as finally there is "in the seeing just the seen, in the hearing just the heard, in the feeling just the felt, etc.", and things being that simple, that direct, that untangled, is what makes the difference, and you can call it what you like.
Fruition is when reality vanishes in very specifically complete way and and then reappears. Primordial awareness is realized when one realizes there is no such thing as primordial awareness that is different from the field of transient manifestation, though there are various aspects of that understanding that can become the focus of attention, which is to say present themselves, and various linguistic ways to talk about this, some of which are clearly more ambiguous than others.
