Post #10, first sentence; Have you removed the intake manifold and checked the starter connections ? You would not be the first to find either a loose IGN to solenoid connector or a loose/missing starter positive cable stud nut.
Trace back the starter positive cable - from the intake manifold, passenger end, to the hot positive junction from the battery - that connection clean and tight ???
As JimD posted, there are relays and connectors to be checked, but unfortunately two of those connections are under the intake manifold.