A look at who Lex will recruit for the Light.
Amanda Waller is a must. It will take some time to convince her, but in the end the goal isn't for them to trust each other (they never will) but for them to see how they could both benefit from working together. Given their shared views of metahumans, I believe they will. Not only will she contribute the designs of supervillain weapons to the Light, but she will contribute the Suicide Squad. Lex knows he needs that, even if Waller doesn't share the idea with him. He's just received a lesson that getting into a fight with Grayven is as impossible as getting into a fight with Superman. But in that very same lesson, he realized Grayven couldn't kill him because it ruined 'the narrative'. Lex has good PR, and he knows how to use it. What better way to rid Grayven of most of his assets than to plan for several supervillains to attempt to enact a new Roanoke with some sort of fake doomsday device and secretly film Grayven murdering these SVs who are supposed to be in prison? 'Well, he already kills supervillains, I guess we the public shouldn't be surprised he'd kidnap them from prison to carry on the job. I'm glad the supervillains are dead, but Grayven is a menace!'
And of course, Lex won't give up on killing the Justice League. The plan was that Grayven's team would replace them as guardians of the earth, but with Grayven no longer 'trustworthy' he'll need someone who can make their own superhero team in the Light's pocket. I believe, after viewing the world's heroes, Lex would find Geo Force is the best choice. Not only is he the leader of a soveriegn nation, like a few past members of the Light, he could lead a new superhero team to Lex's specifications. There are quite a few heroes he could choose to be on the team too, like
La Sangre,
Dr. Moses Lwanga, Fire & Ice (who don't have Paul as beneficiaries in Grayven's world),
Dark Ranger, El Gaucho, or Bilal Asselah, and several members of the Outsiders. Metamorpho, Halo, Katana, Black Lightning, Owlman. None are traditional superheroes. All of them share some of Lex's beliefs. They're not even c listers. And Lex proved in season 2 he can adeptly trick a superhero team into following his lead. All these heroes are available, with Prince Markov as their leader being funded by Lex? When the Justice League and Grayven are gone, Lex could imagine they could defend the earth until he sufficiently upgraded humanity. It will be interesting to see these heroes, or any hero he chooses to recruit, when they realize who they're working for.
Of course, he needs a magic user on his side. Circe is the obvious choice, but does that make her the best choice? He knows Grayven wants the new Light to have 'sane non-supervillain' members. Most magic users will wear costumes, but it's really up to Zoat which background magic users can be called sane in Earth 16. I'd say Thessaly from Sandman would make an awesome addition, but even if Lex could find her she'd probably cut out as soon as she realized politics were involved. Likewise the Shade, Diablo Blacksmith, and Doctor Occult probably couldn't be convinced to join. Maybe
Amy Winston could make the cut? But what would really be interesting, if Lex could pull it off, would be if Lex recruited 'Zatanna' as a member of the Light. If he somehow subverted the orange light's influence on Nabu. Grayven would be reassured, especially with what he thinks is a means of spying on the Light at any time through his construct Nabu's eyes, and Lex would plot revenge on him with Nabu behind his back.
Now, Lex needs someone of the scientific field. Again, it's Zoat's world, he can decide who Lex thinks fits Grayven's definition of sane, but Dr. Niles Caulder seems like a good place to start. Not exactly who I'd think of as sane, but could be different in Earth 16, and could prove to make for an interesting story arc with Garfield and his mother. But if not him, then Dr. Sivana (any of them) would be a welcome addition to the team as well, especially if they're already advancing tech like they are in Paragon.
And of course, Lex was told to stay out of politics. So he needs someone else who knows how to stay out of politics but can certainly pull strings as he wants. I of course refer to the novelist and socialite
Hunter Rose. With any luck, Grayven's never even heard of Hunter's alter ego and he can pretend to be the successful, wealthy, and well connected man that he is, while also pretending to be sane. He could use his connections like Vandal or Ras, to spread the Light's mission internationally.
That's all my top picks for Luthor's new Light. I have a few more ideas, but they'd all be stretching. Some he'd have no way to find, others he'd have no way to convince to join him. Who else might Luthor add to this ensemble?