Evenings with 12-month-old not working
I don't really have advice, I just wanted to say that we are going through similar sleep problems here. DS will also be one in a few weeks. He usually wakes up every 1.5-3 hours to breastfeed, but every few weeks we go through a nasty phase where he wakes every 30 minutes or so the whole night long. So far these bouts have always passed within a week or so, so I assume it has to do with teething or growing. I hope that your DD is just going through a phase and things will level out again soon! Good luck!
It does sound like a normal developmental phase to me, but then there are so many when they're that little!
I can share what we do and maybe there'll be something in it that could help you.
When I'm solo parenting, I take the 4yo to his room to read books (with a flashlight, which makes it exciting and special) while I nurse down the baby (now 22mo, but we've been doing it this way for a goodly while) in the big family bed. When the baby is asleep, I turn on the video monitor and take it with me to tuck in the big kid. I stay in the room with the big kid until he falls asleep (we sing a few songs, etc.), which usually takes anywhere from 20m to an hour. Then I go do my thing for a while, going up to nurse the baby back to sleep as need be. When I finally go to bed for the night, I carry the 4yo to the big (king-sized) bed and we all sleep together there through the night with me between them.
I know it doesn't help much to hear it, but no matter what things will change. It never stays the same long when they're so little! Hang in there, mama.