He retconned Legacy from his "official" timeline, meaning if you want to go by what games are influenced by what games, Legacy and Cornell would be unofficial tie-ins. Iga acknowledges Legacy, as well as Legends and CV64, but doesn't feel they fit into HIS timeline. (prompting mass griping at him from fans for trying too hard to make a believable timeline) Cornell was put into Judgment to give the game more balance and because, despite being retconned, he's still a very popular character amongst fans.
Lords of Shadow being before Lament of Innocence could work, and I'll tell you why. Kojima and Dave Cox already said this game will have no connections to any other game in the series. (though I'm skeptical to believe it will have no mention of anything from the other games at all) Having the game happen between Lament and Dracula's Curse would run the risk of Dracula already inhabiting Castlevania itself since he became its master after he became a vampire at the end of LoI...which would also negate the idea that the Belmonts didn't encounter Dracula/Mathias again until CV3 because Drac was supposedly laying low. Having Lords of Shadow happen before Lament takes away the risk of running into the other games because chronologically they hadn't happened yet, but Castlevania itself is still there and vampires were around long before Dracula since there were Walter and Joachim, and I'm guessing more.
All speculation of course. I could be totally wrong and they might try to slip it in after Lament, but I'm guessing they don't want to step on Iga's precious timeline which is why they are staying away from this game interacting with any others...which means the less interaction with Dracula the better. Or....they could take a big shit on everything and not give a damn. Hell, Judgment already did that, and it wasn't put to the torch.