I find it hard to figure out what things are meant to rule other things out and what things are just inconsistencies. For example, there are comments about there being no bodies, but then we see bodies at the DEO destruction. Leviathan seemingly threw Talia out to her death, but are we to think that was meant to kill her or that they somehow knew Superman was coming and distracted him? Leviathan uses that blue energy to capture everyone including Tiger and Eliza but not Waller?
I have no doubt there are people playing the role of Leviathan at this point. When they visited Harper in the hospital they mentioned having recruited a surprising number of people, and whoever is playing the role of Leviathan sounds more immature than who is meeting with people to actually recruit them, but that might just be due to Bendis-speak.
So the only things I can try to rely on are character motivations. When Lane meets Waller she is under the impression that he is friendly to Superman, and don't forget Leviathan's conversation with Leone which changed their mind about Superman.
Bendis has pointed out the mystery starts with "why" and then that will lead to "who". Sometimes I feel the "why" is Lois (something that Lane has repeated several times). So the who would be her father.
Now, those are good points against him, still, but I am having a hard time considering anyone who a list of reasons against is not possible. And while I might end up ruling out Lane, the process hopefully will help in considering other suspects.