reastie really feel for you with the evening sleep situation. One of the things I think is so hard about this parenting thing is the absolute absence of clarity in a lot of cases about what the underlying problem is. I meanm it would be easy if you knew that i.e. she was for whatever reason still hungry, or she was 'over-tired' and therefore too fractious to settle, or whatever, but when they're still so little, we can't rule anything in or out, and therefore trying to resolve it seems nigh on impossible.
I know you have kept topping up during the evening, but how efficient do you think she is being during these feeds? You see, my only experience is with C that by that time of the day she is tired, and her last bottle more or less sends her off to sleep (we still put her down awake, but she's vvvvv settled and drowsy by then). It might not be relevant to you as you're BFing, but is there any way you can spend an hour or longer just trying to ram as much milk in her as possible (I mean in a humane way of course!)? That sounds stupid now I've written it as I can't imagine you've not tried it.
On a completely different tack, I would say that we have had C in her cot in her own room from quite early on [bad mummy icon], but if it wasn't working for whatever reason, I wouldn't hesitate to change it. I think we can get tied up with what we want to happen (e.g. I want a routine, I want adult time in the evening, I want to breastfeed on demand, I want to do x, y or z), but actually, if it's not working for you and Alice, then maybe you might need to change tack a little bit. Does she sleep if she's with you in the evening downstairs? Does she sleep in your room if you're there? At this point, if I were you, I would take a week (or at least a few days) out of "trying" to get her to do x y or z, and do whatever makes your lives easier.
They're still really tiny and according to much wiser more experienced parents than me, these things are usually phases, and usually pass.
Sorry that's really completely unhelpful, but have just been mulling over your situ and am kind of stumped, but still mulling!
D