I started off by seeing if anyone named Lacey or Lacy was living in Chicot Co., AR and Pointe Coupee Parish, LA (where the cities you mentioned are located). I located the census records with their names and then used the birth data to look through the Social Security Death Index and WWI & WWII Draft Cards and Registration.

Almost all of the census material at Ancestry.com, with the exception of the 1910 Census, and census material before 1850, can be searched using the name of anyone in the household, parents or children. This comes in handy when you are looking for someone whose is a minor and you don't know who their parents were.

Also, you might try using the wild card symbol when searching. Names in the census index are often misspelled. Example: Julie Andrews, with the wildcard Jul* And* There must always be at least three letters in front of the wild card symbol or Ancestry.com won't allow you to use it.