Herb is Bart's...
Uncle
Abe and Mona are Lisa's...
Grandparents
Bart, Lisa and Maggie are Ling's
Cousins
Ling is Patty's...
Niece
Homer and Marge are Bart's...
Parents
Maggie is Homer's...
Daughter
Marge is Homer's...
Wife
Bart is Homer's...
Son
Abe is Bart's...
Grandfather/Grandpa
Mona is Bart and Lisa's...
Grandmother/Grandma
Selma is Lisa's...
Aunt
Bart is Herb's...
Nephew
Homer is Marge's...
Husband