I love a bit of armchair investigating/researching and the two pictures of the P-38's in the ravine being blown up was an easy internet challenge, so I researched this in some depth a while back when I fist saw the pics.
In the background is Mt Arayat which has a different outline depending on which direction you are viewing it from, so using personal pictures of it posted on google earth you can get a pretty good line of sight of where the pics were taken and then looking at the ground terrain (current, so now just approximating) I could make a good guess as to where the P-38 remains (in those two pics) are, if still there.
In my research I came to the conclusion that there where several burial sites around the airfield, so the reports of them being under later runways/development is probably true, but not all the burial sites were, some of these sites were dug up/cleared years ago, also probably true, but some probably have not as there were so many aircraft, so some
could still remain. Lots of 'buts' I know, but

until somebody gets on the ground and digs we won't know for sure, maybe if the Spits in Burma dig is successful it will spur others on elsewhere and maybe Clark Field.