Sentence one seems the most natural.
Sentence two seems a little odd, I think because "very" is rarely used in collocation with "essential"
Sentence three is okay, more familiar register I suppose.
Sentence four sounds like a dogma or religious imposition, but acceptable.
Sentence five is okay, also a little pompous maybe.
Sentence six is like sentence five but more pompous.
Sentence seven could be used but sounds imperative, so the speaker would seem to be in a position of power over the addressee.
Of course, as with everything pragmatics, it will depend on the context and speaker/addressee.
And since you said we should add any to the list, I think a good way to say that is to use an idiom, such as "breakfast is the most important meal of the day"
I hope that helps you! :)