In re the AppleNet card, I believe the attached image shows a more accurate description of what's going on around the network connector. You can see that the pinout of T1 threw me.
The pinouts of transformers T1 and T2 are still guesses---on the card they are mainly unmarked boxes with no ability to see inside. This evening I made measurements with an ohmmeter on the two AppleNet cards I own in order to figure out which pins were the centre taps. I'm basing my guesses on tiny differences in resistance, but this was remarkably consistent across both cards.
As Patrick noted, connections to pins 3,2 or 5,6 of the connector may need to be swapped, or perhaps even both pairs if the current arrangement puts the pulses upside-down on both sides. I'd like to hope that the it's not the case that a single pair needs flipping: if not, the plug has a nice rotational symmetry, and you can turn a crossover cable into a straight-through cable by flipping it upside down. (You would have to do something about the keying on the shell of the DIN connector, of course.)
The
github repo with my schematic has been updated. There are one or two more things I'd like to check, so some additional updates may follow soon.
Unfortunately one of my AppleNet cards seems ill---it hangs during the boot ROM card test some of the time. The problem may be mechanical---it
seems like sometimes it'll make it past the test if I flex the card during boot. I'm not certain of this, though.