Cybersix/WMG

Lucas is bisexual.
This sums up pretty nicely why Lucas is so obviously attracted to Cybersix's male alter-ego, and yet is also so obviously attracted to Cybersix as well. He's obviously attracted to Adrian, spending most of his free time hanging out with him and even asking him to go see a romantic movie with him- at this point, he's not even trying to hide it.
 * I like this theory. It would explain why Lucas is so willing to spend time with Adrian, despite how pissy and prone to walking out on the bill Adrian seems to be.
 * Also remember that the series obviously does not take place in the United States where such a thing would be a touchy subject. No one makes a point of spelling it out simply because it's not a big deal.

Lucas is trying to recreate Sustenance
An early episode of the animated series has "Adrian" walking in on him in the middle of an expiriment. When asked what he was working on Lucas quickly changes the subject. When we see his apartment it's obvious that he's been bringing his work home with him as a corner of his place shows a small but well stocked and recently used chem lab setup. He's seen the stuff before and even retained a sample of it for further study. He's probably keeping a very small vial of it hidden in a safe place so he can study it and free Cybersix from her violent lifestyle.

Data 7 doesn't require Sustenance.
Just a theory, but considering the brain of Cyber 29 was transplanted into the body of a panther, abet a slightly genetically modified one, very feasible. There's not really much evidence to support it, but the show never seems to make any references to Sustenance outside of Cybersix's need for it, it seems strange they never bring up Data 7's dependence on it as well. Even in 'Final Confrontation', when Cybersix has her emotional monologue about needing it the way ordinary people need water, she only mentions that she needs it...Data 7's reaction could be easily read as momentary empathy rather than experienced sympathy. As far as I know, Data 7 was never mentioned as needing it in the comics either, which only gives the theory more credibility since the comic ran far longer than the cartoon.
 * Or, while he was Cyber 29 (being of the same series as Cyber 6) he needed it, but Data 7 doesn't.
 * Jossed? I've read as far as the fourth book (French), and so far the comics don't make any mention of Data 7 specifically needing sustenance. However, it does say that all of von Reichter's creations require sustenance except for his very first (Big Bang), who was a case of No Plans No Prototype No Backup.
 * Maybe Data 7's sustenance refers to food