Well, with input from you both and some tweaks on my part, I've hashed together plans for the red and black drakes. Just tacking 2WINGS on threw errors in the log (as did NOEAT and NODRINK; needed NO_EAT and NO_DRINK), so I used the altered body plan, and that genned just fine. I'm still waiting for some input on details - black drake venom, specifically; trying to learn the structure of the syndrome token, since the Wiki lacks information on the timing properties - and I need to sprinkle biomes in here and there, but if all goes well I should be able to flesh it out some more, and have a release on DFFD for testing in not too much longer.
So I haven't forgotten about this again, I was just somewhat delayed. Thank you for the helpful information!
ETA: Edited the first post to reflect new version. Now found
on DFFD, with the red, green, blue, black, and brown drakes so far. It generates successfully, but testers would be greatly appreciated to see how the little beasties actually perform; my test embarks haven't found any in world (although green drakes, as domestics because of how easy they are to breed, can be purchased at embark), and I don't know if this is because of luck, or because the creature tokens keep them from actually spawning. I especially would like to know how nasty black drake venom is against dwarves or whoever else, so I can tweak either the syndrome or the description or both.