The plural form is auto and the plural possessive is autos' (e.g. The autos' steering wheels were found to be defective.)
Singular possessive: secretary's Plural: secretaries Plural possessive: secretaries'
The plural is lads. The plural possessive is lads'.
The plural is relatives. The plural possessive is relatives'.
The plural form is Mexicans. The plural possessive is Mexicans'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is inches. The plural possessive is inches'.
The plural possessive of stepsister is stepsisters'.
The plural form is echoes. The plural possessive is echoes'.
Coaster's is singular possessive. The plural is coasters, the plural possessive is coasters'.
The plural possessive form of "weeks" is "weeks'."
The plural possessive of bandit is bandits'.