Hmm porbably not, Lingering I prob won't add future ending only a DLC but that is more of a prequel, to when MH and Xander were the leaders.
Also I think you misinterpret the ending (although technically the story in Lingering is fully up to readers and their interpretation of it). Reborn and Illusion are two different endings. in Illusion Keyes is just that, an illusion. But in Reborn that person is actually Keyes been brought to life, only his memories are wiped ^ ^ hope that somewhat cheers u up a bit