Here's a good, detailed link about that code, which may also help you out.
http://www.easterncatalytic.com/education/tech-tips/the-misleading-nature-of-the-po42o-code/
Damn, that sucks about the new tranny being a bum! That same thing happened to me, I know the feels.
Try some purple power to clean up the tranny grime (that sounds gross lol)
Yeah, if not EBP, it could be Arctic Blue Pearl.. pretty identical though slightly darker I believe. The pic you posted up the color looks identical to my car.
D16Y7 exhaust manifold from factory has catalytic convertor attached to it like in this pic:
If that's not what you have, at some point your manifold/exhaust was replaced already and you should be fine.