There are actually two issues concerning this topic: There is a comprehensive article on the topic on grammar girl: What would be correct in this case and why?
In my experience, the spelling checkers get confused by contractions. I have the following sentence: The indefinite pronoun 'everyone' is a singular pronoun.
May i have everyone's attention,. The expression commonly used in both the affirmative and negative. Would the noun following everyone's be plural? Joe got everyone's attention and started to speak.
In fact, to catch someone's eye is an idiom, not eyes. the question is not about everyone being singular or plural. Your deduction, that not everybody's cup of tea means not to everyone's liking, is absolutely correct. The possessive form is everyone's (the form everyones' is incorrect).example: An example would be it flew over everyone's heads, or it flew over everyone's head.
Everyone who is coming will receive a gift. Are the words everyone and everybody singular or plural? Unless of course you’re a buddhist or a cat, in which case everyone has multiple lives and both would be correct, depending on context. Should it be everyone's, everyones' or everyones?