I really hope oda turns it around by pitting luffys freedom against his destiny, but i dont think so. I dont even know really what was the point, I mean his awakening could have had these powers either way.
Yeah its kinda dissapointing, and made one piece feel less special
Those are trilobites, part of the arthropod phylum. They have exoskeletons (i.e no inner bones), so they would probably look quite a lot like their fossils. Comparing them to vertebrates like humans (or dinosaurs, or whatever) in this context makes no sense.