It is both. It is reasonable. To the extent it evaluates objective evidence, including organized matter that behaves according to predictable laws, it is scientific.
Finding unorganized matter would in no way lessen the likelihood of ID, because the designer can do anything and everything.
The designer is not defined or made evident by possibilities and potentials but by what is actually designed, built, and set into motion. The presence of unorganized matter that does not behave according to predictable laws would be uncharacteristic of an intelligent designer, and thus serve to undermine its presence or activity. Intelligent designers are not by definition omnipotent or able to do just anything. They may be bound by physical laws.
Finding a human in the Jurassic would be devastating evidence against evolution.
Nope. It could easily be explained away as an anomaly, much as when an old spark plug is found embedded in rocks that date "millions" of years old.