Spoiler: Response to a couple of your points
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To the first point, that was actually the skeleton from the end of the first movie that Dr. Grant, Ellie, and the kids were hanging onto during the final raptor attack Spinosaurus was on a different island, Isla Sorna (Lost World and JP III took place there, JP and JW took place on Isla Nublar).
Absolutely. My spouse has experience with raptor training and handling, so I've seen it up close. No reason it couldn't be done with dinosaurs like JP's velociraptors (best to just pretend they say that because Deinonychus would be too hard for kids to say).