Are they students?
If they are not students and over 18, then their income IS a factor in whether or not you cannot claim them on either your federal or NJ return if they made more than $4,700 for federal.
For NJ, they must be 21 years old or younger if they are a full time student over 18.
“Dependent unemployed unmarried child, that is, a son, daughter, stepson, stepdaughter, legally adopted son or legally adopted daughter under the age of 19, or under the age of 22 and attending an educational institution as defined in 43:21-19(y) on a ” N.J. Admin. Code § 12:17-7.2