This whole OMAC blowup is quite hilarious. I've been considering the OMAC theory for a few weeks now, but what got me on to the idea initially was a questioning of why WB decided to do Suicide Squad second (instead of Wonder Woman or Aquaman), and then why Suicide Squad has such a strong metahuman focus. But when Viola Davis revealed that she'd signed on for three films, that got me thinking that she has a part to play in Justice League, and therefore BvS, Suicide Squad and Justice League are more closely tied than previously thought. Together with Bruce Wayne's involvement in Suicide Squad, that made me strongly consider Brother Eye as the Justice League threat. Then from there the evidence continued to pile up. The "Alexander Luthor, Jr." and "Kord Industries" references are just icing on the cake.
Zod could most certainly serve as the basis for an experimental OMAC. After all, LexCorp does get his body from USAMRIID, and the OMAC virus is a LexCorp/DOD creation. And instead of the Brainiac-13 virus, it could be derived from the Kryptonian liquid geo tech (you know, the stuff that can actually hurt Superman). Brother Eye could be based in the Lex/OS, and could possibly hijack an ARGUS/Wayne metahuman-monitoring satellite.
It certainly makes more sense that Bizarro (who'd literally be just like Zod) or Doomsday (who has neither the origins nor the power set concluded from the trailer).
On similarities to Ultron, there's a CBS show called Person of Interest that has a rogue, sentient A.I. that operates nearly exactly like OMAC does in The OMAC Project (how Lord uses OMAC initially). If WB went that route, it would seem nothing like Ultron at all.