Si desea pasar una matriz, debería ser mejor escribir
@applicants = Applicant
.where("applicants.first_name LIKE ?", "%#{people}%")
.where(status: ["new", "in-review"])
O use squeel joya.
@applicants = Applicant.where{ (status.in(["new", "in-review"]) & (first_name =~ "%#{people}%") }