While I honestly have no idea what happened to them, my guess is that Chris Savino and the rest of the team for the later episodes must have forgotten they existed!
Either that, 或者 maybe they decided that they wanted to focus 更多 on 《嗜血法医》 in the '00s. Notice how Dee Dee got considerably less limelight episodes when the '90s were over.
It's a shame, because there were a couple of things those characters brought to the series. For one thing, they gave the writers 更多 scope for episodes that focused on Dee Dee (like I said, there weren't as many episodes about her in the newer seasons), but also they added some cultural diversity to the otherwise Caucasian cast of characters (which is important because many people do feel under represented in the media - 你 can see why).