I don't know is Rei has some other link to the Red Cross Book, but I could find only this one:
Red Cross Book Translation
As for Asuka, I think I sypathized with her more towaards the end than during the rest of the series, because it appears that she's a really fragile creature, even more fragile than Rei, with lots of fears and humanity. I started liking Rei during the first part of the series, than I liked Asuka more than her in the end.
*spoilers*
After the creation of the third Rei Ayanami, it's clear that when Asuka accuses her to be a doll, she's not completely wrong, after all. Rei's only sign of humanity is the sight of her tears in one of the last episodes, but we're confused about this reaction, because she's the third, not the first one. The first Rei (the kid killed by Ritsuko's mom) was an annoying and cruel (maybe also sincere, but still I think cruel) creature. The second one? About her we don't know much, only her affection for Ikari Gendo. About the third one, finally! we see a sort of human reaction, but it's too late IMO to feel a deep sympathy, the same sympathy I feel for Shinji, Asuka, Misato and yes, Mr. Kaji. Even Shinji, who liked Rei so much during the rest of the series (and he finally discovered Rei is a clone of Ikari Yui) is unable to symathize with her, and feel rejected by the whole thing. Asuka seems to go mad after the battle with the angel, and she starts acting in a weird way. She feels not adequate for her role, that's why she acts like a B*tch, as you said in your post... Her mind is not well balanced and she seems to suffer of a mental breakdown after being defeated by the angel and being saved by Ayanami Rei.