Sure "it" can be employed in all of those constructions and others, but soem of your examples could use changes. When I see a colleague of mine composing this kind of phrase, I generally indicate that it's a kind of previous-fashioned influenced valediction which, probably, today, a local English speaker https://petskyonline-onlinestrore.blogspot.com/2025/07/top-10-aquarium-essentials-for-new-fish.html