Hi Chris,
Oestreicher's story is certainly an amazing one. Since you've already been researching him, what I've provided is probably old news already, but just in case it's not (and for the interest of others)...
From what I can find, the 3rd Pursuit Squadron (Provisional) was formed on or shortly after January 15, 1942, using pilots of the 3rd Pursuit Squadron that had been evacuated from the Philippines earlier that month, as well as a few replacements fresh from the USA. If Oestreicher was one of the Philippine vets, I would think there's a good chance of him turning up on a group photo or list, as that campaign is fairly well documented. Perhaps research of 3rd Pursuit Squadron or 24th Pursuit Group would turn up something.
The only post-Darwin raid info I found of Oestreicher on-line deals with the repairs to his damaged P-40E "Miss Nadine" and his unsuccessful attempt to ferry the bird from RAAF Daly Waters to Amberly. I am sure WIXers will enjoy the quality profile artwork of "Miss Nadine" (Be sure to scroll all the way to the last page if all you want to see is the profile!).
http://www.clarkjanson.com/histories/PE ... report.pdf
I also found this link interesting, as it identifies the pilot of the Zero which initially attacked his flight:
http://www.netherlandsnavy.nl/Special_darwin.htm