Unfortunately you show with this post that you have zero inkling what my discussion points are! If there is incest or not between Lena and Seymour is inconsequential for the main point.Also, she hided Seymour's identity in order to avoid Lena getting mad when she discovered her mom lied about her real father... If you want the incest content so bad, just make it your headcanon. Maybe someone does an incest mod at some point.
Seymour is a very successful and connected businessman. It would be no problem for him to find/hire top- and supermodels for his photo hobby, BUT he chooses Lena, a rather unknown, relatively fresh model. He is very much simping over her, helping and favouring her on most paths. He is doing more for her than most of her family ever did.
Why would a shrewd businessman do that? There are only two options: Seymours sees in Lena the daughter he never had or she really is his daughter.
I once again mention the fallacy of your construct. Photos do not have to be the correct ones, esp. when showing them to a small child. Even if the photos are correct, people change and some persons change more than others. A beard or not, a different hairstyle is often enough to throw peoples perceptions off!That's a stretch and would be some bad intentional obfuscation in writing from Eva as it just doesn't make any sense. Seymour is a celebrity. Lena's seen photos of her father.