The syntactically dangerous all and plural in specifications

The simplest way to write a sentence describing a property of each member of a set is to use each, which is grammatically singular. When using each as a subject of a sentence, the verb of the sentence must be singular. Consequently, also the complement of the sentence must be singular. When the complement is singular, the grammatical implication is that the complement applies to each member of the set. Thus, the simplest way to be precise about intention is to talk about properties of each member of the set and use all when the intention is to talk about properties of the whole set.