Re means again but would not cause confusion with another word so no hyphen. Example: I must re-press the shirt. Re means again AND omitting the hyphen would cause confusion with another word so hyphenate.

What is reintroduced mean?

transitive verb. : to introduce (someone or something) again efforts to reintroduce the animals into the wild They'd been touring hard, reintroducing themselves to audiences nearly a decade after going their separate ways.—

Is reopenings a word?

Plural form of reopening.