K.E.
As another mom suggested, I would move the 2 year old out of the room for a few nights. Let her have a "sleepover" with your older daughter. Also, try bananas as a snack before bed as they contain tryptophan like turkey and may help lull her to sleep. Or perhaps even warm rice cereal with bananas. I also did the water instead of formula trick in the middle of the night when my oldest was 10 months old and wanted a bottle and can confirm this works if you are consistent.
Best of luck - my kids are 4.5 years, 2 years, and 3 months. Not quite as close in age as yours, but I do know that it's tough to have such young ones close together.
K. E.