Some information taken from the Internet Movie Database.
"Laura Ingalls Wilder"
Melissa is the youngest person ever to receive a star in the Hollywood Walk of Fame. She was one of 500 girls to audition for the part of Laura Ingalls for the "Little House" movie and TV series. She later appeared in TV remakes of "The Diary Of Anne Frank" and "The Miracle Worker" (the latter produced by her own production company, Half-Pint Productions), and became a staple of the TV movie aura. Formerly married by actor Bo Brinkman and currently married to Bruce Boxleitner. The story of the birth of her second child could take a whole 'nother web page, but it was a difficult birth, and the baby boy would eventually be named after Michael Landon, the man who had guided her acting career. In addition, she currently holds a position as the President of the Screen Actors Guild.
"Mary Ingalls Kendall"
Like the character she played in "Little House", Melissa Sue Anderson started out the shy girl, preferring to read books than climb a tree. But she eventually began her career appearing in TV commercials and several series (including "The Brady Bunch") before becoming Mary Ingalls. Years later, after appearing on an episode of "The Equalizer", she married producer Michael Sloan. The Sloans have two children.
"Carrie Ingalls"
You would be surprised to know that Lindsay Sidney Greenbush is/are actually twin sisters--Lindsay (real name: Rachel) and Sidney (real name: Sidney Robin), daughters of actor Billy Green Bush. "Little House" was their only major acting appearance (aside from cameos in "Electra Glide In Blue"). They haven't acted since then, and both actresses have started families. But, they occasionally tour conventions and don't mind talking about the show that made them famous.
"Isaiah Edwards"
This left-handed actor was the son of a stuntman. He made his debut in a small role on the classic TV series "Lassie". He usually played the bad guy in Western films until Michael Landon cast him as the drunk vagrant-turned-father figure Mr. Edwards on "Little House". Both French and Landon became good friends and appeared later on "Highway To Heaven". During his hiatus from "Little House" he starred in the short-lived but cult comedy "Carter Country". He passed away from lung cancer in 1989 shortly after "Highway To Heaven" ended production.