Hello sleepy (or should we call you MrsE?!)
Wow genuinely, I could have written your post word for word (except for the 2.5yo DC) 5 months ago. Some people talk about a 4 and a 6 month sleep regression, for us it was just one bleary-eyed horror story in the sleep department. At 6 months I called in a sleep consultant because it was doing me in. I epically failed to follow her advice (the crying I was told to expect just seemed never ending with my DS and I couldn't bear it) but a lot of what she said was very sound. You might know most of this already, and it's going to be a long post, but in case it saves you the £300....
The pattern is typical post 4 month sleep maturation. For the first stretch, melatonin (sleepy hormone) plus the tiredness of the day keeps 'em down. Between 12 and 2am melatonin drops off and cortisol (wakey hormone) ramps up quickly to meet the start of the day. So by about 4 or 5am onwards (becoming 3am in a couple of months' time) the chances of successfully getting your LO back to sleep without the use of serious sleep props is virtually nil. That's why they say to try and drop any night feeds after 3am by 6/7 months - because it's the devil's work trying to get them back into the cot awake.
For the feeding - she may well still be hungry enough for a night feed (or maybe 2 at that age) but she's currently snacking. For preference there would be a couple of genuine 'hunger wakes' over the night period (like she prob did at about 3 months before the bastarding hormones got involved) and that would see her through to the first feed of the day. My DS was never really that hungry at 7am because he'd been snacking all night.
So the advice was to choose 2 time slots (e.g. 10-11pm and 3-4am) where you will feed your LO when she wakes. Don't wake her at those times, but during either of those windows (or the next wake afterwards) go straight to her and tell her it's time for milk and feed her. Any other time, you tell her it's time for sleep and soothe her some other way (ideally in the cot, e.g. patting, shushing, or whatever she prefers). The idea here is that her body adjusts to the feed times and these become regular (meaning you can drop one, then the other, when she no longer needs them in due course). She no longer bothers to call for you at other times because she knows she won't get milk, but equally she knows milk will come later so she's relaxed about this.
So I came a cropper because I just couldn't find anything other than boob that my DS would accept without a lot of protest, and I couldn't deal with the distress. I my head it makes total sense. In my heart it just felt ghastly.
Hope that helps (you or anyone else reading) x