OP I can offer a little advice as I spoke to a sleep 'expert' - well, a nice HV who had done a course at the Millpond Sleep Clinic - she was very helpful.
At 7 months a baby 'should' (of course all babies individuals but this is a general rough idea) have a nap of at least 45 mins in the morning - mine has a nap at 840 ish - earlier if has woken early.....sometimes later. but always about 45mins/ an hour.
second nap after lunch - or around the middle of the day. I have found this has got later as my DS gets older - often is 1-3 - sometimes earlier 1230 - 2 ish. - he started sleeping longer naps after 6 months never did before, but now regularly does 2 hours in his cot at this point.
I can give one really really good tip that worked for us - stop the milk link to sleep. I know it's a faff to get them to settle - but DS definitely sleeps much better when he has fallen asleep in the cot himself not gone in drowsy/ half asleep from BF.
Have solid then milk - then a break? To make sure not sleepy - then settle in cot, I stay in room , sing/ pat/ tidy up ...
My DS actually goes into bed at half 6 - that's not something I pushed, just naturally started doing that- he is then up at 6/630 - perhaps that nap at half 6 is just bedtime? I find that if he has a nap after 1 in the afternoon ie. ending at 3 - he doesn't need the later nap. But if its earlier he has half hour in buggy at about 4.
and..feeding. well, I think it's very very normal to have one big feed in the night at this age - my DS feeds twice normally - sometimes more, but I am really trying to stop that.
Could you switch to a carton of formula at night? I ebf as well but at this age, once taking food I was relaxed about formula.
Two options. Either feed at night for a week or so to see if it settles and sleep comes back. I know it's hard if they sleep through then stop but two milk feeds in the night doesn't seem that bad, especially if the early one is so small - what about trying to fill up then with a bigger feed and a wake up?