Help! Searching for foster siblings from St.Louis MO

My name is Peggy, I grew up in a family that kept foster children. Through the years and among the 17 kids we kept, there were 2 kids (not related to each other) that was part of our family for several years. The boy's name was Ricky Thomure and we know he went on to be adopted with a bio brother by a couple that were formerly a nun and priest. The girl's name was Dottie Sitze and she was returned to her bio family, several times. I was the youngest in our family and these two kids were younger than me, so for the years we got to keep them, I was the "big sister". I have many more details (not listed here) on the girl, Dottie. The time frame would've been in the late 60's and early 70's. Our last name was Humphrey and we lived in the suburbs of St.Louis Missouri. I have been searching for years, but keep running into dead ends. I would love to find them and hear how their life stories continued, to share photos and school memorabilia with them, and overall just let them know they were so loved by our family. If anyone out there has suggestions on what I could do to find them, I am open to suggestions, but don't really have the financial means to pay someone to help me.