I think she's definitely ready to move toward 4hr EASY as it does seem like she's UT for naps. Generally A times need to keep increasing slowly so you don't have to do big jumps all at once, I would try a 1.45hr A time and see how she does and go from there, but she can probably move to a 2hr A time pretty quickly. Getting her on 2 solid naps and likely a CN is actually probably going to help nights. That said, there is a pretty big sleep regression at 4 months so often nights go completely wonky regardless. My DD was doing 7pm-3/4am and then at 4 months she was waking at 1am and 5am, now at a bit over 5 months we are back to 7pm-4am.