M.M.
Both of my kids have been in bed by 7pm - or ealier, my 5mo goes to be around 6 every night - by 8 weeks.
It was not a natural transition for my kids. I just started their bedtime routines at that time and that's when I put them down. Takes a little playing around to find that sweet spot of time. That's how I got to 6 with my daughter - she's just ready at that time every night, and goes down for 11 hrs now.
I would eliminate that last nap and just put her to bed between 6:30-7.
You might find that she drops the 3am feeding.