What does it mean to "really know" something? I might not "really know" something if the estimated standard deviation is +/- 10% when I really want it to be +/- 0.1%. While for some things the estimated error is +/- 0.00001 % or smaller. (For that matter, Heisenberg says we'll never "really know" the position and velocity of a particle.)

We don't "really know" the effects of the ice ages, but we know a lot of the effects. We don't "really know" what the effect of a major meteorite strike, but we have some idea of its effects.

We know enough about both topics to draw some reasonable conclusions based on multiple trails of evidence.

We know how to date things well enough to be able to date things far better than "10 million vs 1 billion" years. Creationists love to challenge the potassium-argon dating used in East Africa for early hominid remains. While there was controversy early on with, say, the dating of the KBS Tuff, as http://www.talkorigins.org/indexcc/CD/CD031.html covers, that link points out there are now multiple different methods by different people which agree on a time around 1.9 million years ago, with a +/- of about 1%. This is a well-studied topic because understanding it is so important for the story of human evolution.

I have read enough about the science behind reconstruction from bone fragments to get the sense that it's a reasonable science, and to realize that it is a specialized skill that depends on intensive understanding of many different animals. Just because neither you nor I can make much sense of those fragments doesn't mean that others cannot.

In any case, there's no reason to trust their interpretation. As I pointed out before, Lucy is not the only A. afarensis fossil. AL 444-2 is the complete skull of an A. afarensis male. It's larger than Lucy; the assumption is sexual dimorphism. That makes the AL 444-2 skull even less like a chimp than Lucy, yet they are of the same species, which you say is a chimp.

Furthermore, reconstruction is eminently testable. Here are two I thought of: 1) How well does the reconstruction match more complete skeletons found later, and 2) create a 3D model of part of a known skull and do a double-blind test to see how well the reconstruction matches the skull. If people mostly "made stuff up" then it would easily be discovered.

The New Scientist link is clear to say "He stresses, though, that the analysis, which he will present at a meeting of the Paleoanthropology Society in San Francisco next week, also confirms that the other 88 fossil fragments belonging to Lucy’s skeleton are correctly identified. And the mislabelled baboon bone fragment doesn’t undermine Lucy’s important position in the evolution of our lineage.".

Furthermore the actual paper says "This work does not refute previous work on Lucy or its importance for human evolution, but rather highlights the importance of studying original fossils, as well as the efficacy of the scientific method."

And again, why is all of your focus on Lucy? We have other A. afarensis fossils which give us even more details about bipedal adaptations.

You write "they are in the wrong place". And your point is ... what exactly? Evolutionary theory predicts that existing structures get adapted for new uses, including to change place. Also, "right place" implies that somehow those early feathers were in the wrong place. They weren't. They were only in a different place.

You write "There must be a birdlike animal that has partially formed feathers on it's wings". No. Feathers came first. They were always fully formed, but in a different form. By analogy, there's no such thing as a giraffe with a partially formed neck, only earlier giraffe-like animals with a fully-formed but shorter neck.

"Combine that with scientists' desire for fame". What a silly argument. First, scientists are humans, and yes many humans want fame and will do short-cuts to achieve it. Do you have any evidence that scientists are more prone to that than other fields?

That said, there are many easier ways to fame than to become a scientist, fame built on sketchy research is fragile, and one way to become famous is to show that someone else is wrong or even a fraud. For example, Ioannidis became famous as a result of his paper "Why Most Published Research Findings Are False".

Furthermore, over time it becomes more difficult to produce sketchy new results which are consistent with the existing body of work. At some point it's easier to do non-sketchy work. (Like the old observation that it was easier to go to the Moon than to fake the Moon landing.)

Most of the scientists I know are not in the field to become famous, and they know they will never be famous. How many famous paleontologists do you think there can be? How many paleontologists are there?