Plastic Man and Fire didn't have other characters sharing their namesakes. A character's popularity is subject to change, and the DCU with its frequency of revisions offers that possibility to the Vietnamese Thunder and Lightning. Similar to Wind Dragon in the JLU being an updated Samurai. But my readiness for putting the Pierce sisters in limbo is mainly that I feel they hinder and pigeonhole Black Lightning rather than anything revitalizing.
Most people probably are aware of Lana Lang as well. I'm not saying that Vale or St. Cloud are heavyweight romance options for the Bat, but they are examples of pre-existing romances that have "the high ground" compared to newer romances regardless of their race.