When being at the Sunshine settlement, the build menu claims there are 17 settlers but I can only count 12 and a cow (the robot has disappeared). There are 5 dead ghouls there though, don't know if the game counts them among the settlers. It's ghouls I had to kill when cleaning out the place about a Real Life ^TM week ago but I'm pretty sure they didn't count at the beginning when the first settlers moved in.