Hiya,
Two thoughts for you, what do you think?
(i) Why not try extending the wake times again? Or did you do this very recently? I would only extend one at a time, though, and if she's really sensitive to OT then only by 5mins. Maybe try the first A time to begin with, although as I know my DS always preferred a slightly shorter first A time, you could start with the second if you think that would be better for your DD. I agree it does sound like she's slept a lot by lunch time, and that may well be why she struggles to have a good long sleep after lunch.
(ii) Don't worry about a strict feeding schedule. EASAE is fine, if she's not hungry when she wakes, although I agree it's probably not such a good idea to plan to feed to sleep. However I wouldn't really worry about that too much if she usually gets to sleep by herself, sounds like you're doing REALLY well on that front
You could always bring that 4pm feed forward so that she's not going straight from feed to sleep. What happens after that? Does she cat-nap? Lots of babies cat-nap and cluster feed in the evening, so don't worry about waiting a full 3h until the evening feed.