Unfortunately you don't say what 'the following' are, so can't answer the question.
None of the examples provided. Can you please provide me with the plural nouns you want me to check?
The correct spelling for the plural noun of "screech" is "screeches".
No, "memorys" is not a plural noun. The correct plural form of "memory" is "memories."
That is the correct spelling of the plural noun "lunches."
The correct spelling of the plural noun is "cultures."
That is the correct spelling of the plural noun "quays" (wharves).
The correct spelling for the plural noun of "screech" is "screeches".
The spelling of the plural noun, enrollees, is correct.
That is the correct spelling of "trainer" (an athletic coach, or animal tamer).
The correct spelling of the plural noun is nostrils(nasal openings).
That is the correct spelling of the noun "colonist" (a settler, plural colonists).
That is the correct spelling of the plural noun fifths.
That is the correct spelling of the plural noun "tenants" (renters, residents).
That is the correct spelling of "dingo" (Australian wild dog).
No, "memorys" is not a plural noun. The correct plural form of "memory" is "memories."
That is the correct spelling of "firefighter" (fireman).
Pianos.
That is the correct spelling of the plural noun "necessities" (things generally required).