Love the parallels at play between Zeno and Grace.
He's most definitely some sort of Wesker clone, and she as it turns out is most definitely NOT a clone of anyone. And Zeno's the one to mistakenly break it to her her "origin," which if it were true would have been a point of connection, of relatability, between the two.
They both wear glasses that are debatably prescription or not, though Grace, being in a near constant state of vulnerability, doesn't wear them throughout the game with the default skin; in turn Zeno only takes his off when he is at his most vulnerable: after he's unwittingly cured himself of his powers with Elpis and no longer has great levels of invulnerability.
Also Grace's are transparent, while his are clip on sunglasses attached to a normal pair of debatably prescription ones, which imply he may have the inner potential to be more transparent and honest as a person if he were just able enough to distance himself from the identity of Mr Sunglasses himself Albert Wesker.
Alas he's no Grace, who doesn't wear glasses to hide, but instead to see (at least, perhaps just to not strain when looking at screens), and that sets the two apart subtly, mirroring the larger difference that's revealed later when it turns out Grace is not a clone at all.
Zeno appears to function as a "good enough" clone of Wesker, and Zeno and Victor Gideon assume Grace is the perfected clone who successfully contains transferred memory pertaining to Elpis, so to Zeno, to meet the sort of "perfect execution" of what you yourself are an attempt of must have been slightly intellectually thrilling, or perhaps subconsciously intimidating. Maybe that's why he lets Victor Gideon deal with her first, and also why Zeno seems to not respond with excessive, condescending irritation at Grace's anxious demeanor in a way a stereotypical villain might if they were the sadistic type.
That "weakness" of personality (cough, normal ptsd and likely autism, cough) contrasts against her supposed "scientific perfection" origin that may come across as soothing to him, if he has any potential feelings of inferiority towards being a clone of Wesker. Her bluntly presented and very obvious "defects" don't prevent her from being "perfect" and thus what they're seeking.
Of course it turns out none of that logic actually applies to her. And proving how fundamentally different they actually are, not long after he realizes this, he dies. He is so wrong he engineers his own death by pure accident, because he could only see things tinted through his own origin (Wesker and cloning; sunglasses) and Gideon's faulty intel, but not through the clear sight of the actual truth, something Grace is the one to figure out and perceive properly.
