It sounds like you are doing everything you can...maybe your older baby is waking due to hearing your younger one when she wakes up at that 5am hour?
Have you traveled recently?? Because my daughter (also 22 months) slept like a dream baby for the first 8 months and when we went on vacation for a month to Chicago, I think the time zone change really messed up her schedule (because it wasn't the same after we got home for awhile). My other child is 8 years old and it was much easier to get him back onto his AZ time zone schedule, but it took me a good month before we got her back into her typical routine. Hang in there...it seems like you are doing all the right things and it'll get better. I do know of a local mom in the Ahwatukee area (she is in my MOMS Club) that is a certified baby care specialist...she deals with a lot of sleep issues! If you are interested, let me know (I'd like to get permission from her before I post her name and ph# online - although she probably wouldn't mind the "plug").
By the way...I saw the article on your business awhile back in the AFN and I use to work with your sister's husband in Chicago...small world, huh? Good luck and let me know if you want that ph#! L.