Were the GT40P's, the Explorer intake manifold and the 65mm TB that were fitted to the AU's, all basically taken from the F-series truck range?

I dont know about the F-Series, I think they were running the SOHC 5.4L modular engine by that stage.

The Windsor in our AU's is from the Explorer 4WD, hence the name

Oh right.
One bloke has a S/H TB off an Explorer or similar F-series model for sale for $150 and when I asked if it was a 65mm TB he said he just measured across the manifold opening and got 69mm so I just assume it will be a 65mm TB. Would that be a correct assumption?