Vilnoori. I'm not a scientist of any kind, though I try to keep up, particularly as it applies to natural history, and find that as the study of biology and geology become more and more techinical, the definitions do too. I hesitate to call it merely jargon, but different disciplines study the fossil evidence and its record from slightly different perspectives and for reasons that are germane to their areas of research. I kinda doubt it's a matter of a cut-off date but rather a question of relevancy to the kind of study they're pursuing.
Biology-Online has a pretty good set of definitions, diferentiating among a number of disciplines; such as in geology in contrast to paleontology.
http://www.biology-online.org/dictionary/FossilAnd please understand that I mention it not because I take issue with what your wrote but just in the interest in precise language when possible. You know how discussion can go all non-linear and become protracted over what amounts to the nuances of words rather than their intended or conventional meanings.
This topic on h.floriensis and whether its erectus or something else, and how brain and skeletal size relates to its origins, is very interesting. I see efforts to place it someplace on the family tree, which we typically visualise as a trunk with a few branches, which not coincidentally reflects the relatively few fossils we have. I think if we could somehow recreate a model of the ecosystems back then, over the last 4 or 5 million years, perhaps we could understand the proliferation of different populations and species of ancestral hominids, only a few of which presumably are known. Of course this takes us to a term which is even more difficult to pin-down as far as its definition: species.
I kinda favor abandoning the tree trunk and branches model of the evolutionary journey and instead prefer the concept of radiating populations in which are carried a wide variety of traits some of which linger only to disappear or re-emerge, depending on the way climate changes or natural catastrophe or how it confronts competition. So instead of a tree it looks more like a bush with the ability of branches to occasionally re-fuse into a single line. Humans look like they've developed a barrier against fusing with non-h.sapiens when our reproductive strategies incorporated the uniquely human cognitive abilities that consititue language and culture. In other words, it's unlikely that an erectus, no matter how strong or successfull as a hunter it might be will be able to regularly copulate with h. sapiens since h. sapiens are socially structured, no matter where we find 'em or whether they're stone age or cyber-age, in such a way that a prospective mate needs to bond socially before being granted priveledges. Giving species names as we do with fossil primates is a slightly different process than what we do with living populations, for obvious and necessary reasons.
For what it's worth, I think h.floriensis was a diminutive erectus. But if it were a nano-neanderthal, who'd be the wiser at this stage of the research. It's really not that important except as fodder for discussion.
Hair cover. I don't buy the notion that hair and humans had to do only with retaining heat because we see that hair cover in so many mamal species, especially in primates, does so much more as far a communicating the owners fitness and status and sex, as well as protect the skin (or hide) from exposure to damage.
I've been researching on the internet some of the reports from Eurasia where relic populations of everything from miniature homids to neanderthals and erectus and the way they are described as hairy is interesting...sometimes it's sparse, sometimes it's described as a pelt..and even here in North America, their seems to be a range. How indicative of primates.
Really, if sasquatch can exist using primate intelligence and superior instinct for cryptic behavior, why not more than one population, or species...who knows if they don't reproduce. We suspect wolves and coyotes do. We know that horses and asses will. And humans? Who hasn't heard stories?
Antarctica is an "interesting" place to live and work, You're a biologist. If there's any particular aspect of field study which is relevant, find a researcher and let 'em know you're interested. It is impressive to see the scale of "big science" at that level. Cheers