Re: Lyta & Talia, I think she has the misfortune of starting on the wrong foot with the command staff. The first time she meets most of them (only Garibaldi was around when she was first on the station), it leads to one of their friends being revealed as a traitor, and while it wasn't her fault, she was the one who literally triggered it. Then the next time she turns up, she's been hanging out in Vorlon space and acting strange (Sheridan & co literally admit to finding her creepy). So they never really see her as a human like they did Talia.

(Lyta's fall due to her being mistreated by the 'heroes' is one of my favourite minor character plotlines on the show, because it shows how even people who act with the best intentions and end up hurting others without relaising it)