Why is the Warden Amell listed as the eldest child of Revka? I don't believe the Codex, ingame conversations, or the timeline support this. IMO, based on the knowledge I've obtained in DA2 and the conversations heard in DA2, Amell Warden is not the first/eldest child of Revka. First off, Leandra remembers her cousin losing the children and speaks of it in a way that makes me think she really witnessed some of Revka's children being taken and was nearby, this makes me believe that at least the first of Revka's children were taken when Leandra was younger and before she left Kirkwall. Second, the timeline doesn't really fit for the Amell Warden to have been that first born child. Third the codex doesn't support the statement either.
My main point is that saying in the history that the first born child of Revka that was taken and placed in Ferelden isn't supported by any in game knowledge, nor is it supported that the Amell Warden is the first born child of Revka.