I disagree because Tiffany, functionally, is still a superhuman. She's still a part of the 8th line, whether she was accepted or not. That's how the infection works.
Aglaecwif still treated Ella as a chosen. Valravn still sees Ella as a spawn of the Body. Even the scene from last update has us see that the 3rd saw Ella as his heir. Now that we know that what the MC is seeing is memories from their blood in the vial, not it directly referring to him. The 4th, on the other hand, calls her a failure, likely because she failed to unlock the memory trait. Not to mention, Ella was in the same park as the 3rd and 4th when MC got infected. If he really didn't see her as his child, he could've easily just killed her there. Not to mention her Level 5 evolution scene when the 3rd, likely, was talking to her.
Also, if I'm not mistaken, the Moon Twins were also turned via injection and they're still treated as chosen/heirs.