The noun 'insurance' is an uncountable noun with no plural form. Insurance is expressed as some insurance, a lot of insurance or insurance policies, insurance companies.
The possessive form for the noun insurance is insurance's.
The plural form for the noun auto is autos. The plural possessive form is autos'.Example: Both of the autos' owners had let their insurance lapse.
The plural form of the noun tree is trees.The plural possessive form is trees'.Example: All of our trees' damage was reviewed by the insurance company.
Coaster's is singular possessive. The plural is coasters, the plural possessive is coasters'.
The correct form is "its" for the possessive form in the plural. "Its" is used for both the singular and plural possessive forms, without an apostrophe.
The plural is briefs. The plural possessive is briefs'.
The plural is lads. The plural possessive is lads'.
The plural is trollies. The plural possessive is trollies'.
The plural is relatives. The plural possessive is relatives'.
The plural is stations. The plural possessive is stations'.
Museum is singular. Museum's is singular possessive. Museums is plural. Museums' is plural possessive.
The singular possessive form is heart's; the plural possessive form is hearts'.
The plural form is homes; the plural possessive is homes'.