'Everyone is' is the correct version. Although 'everyone' sounds like a lot of people, it is actually a singular pronoun, and therefore requires a singular verb. Same goes for the indefinite pronouns everybody, anybody, anyone, someone, somebody, anything, everything, no one, nothing.
Consequently, what is the difference between everyone and every one?
Everyone vs. Every One. The pronoun everyone may be replaced by everybody. It is used to refer to all the people in a group. Written as two words, every one emphasizes each individual who makes up a group, and it means each person.
Do you capitalize everyone in Hi everyone?
Answer: The first word, all nouns, and all titles are capitalized in the salutation. That's according to The Gregg Reference Manual. Gregg says nothing about the last word. As pronouns, all and everyone would not be capitalized unless they were the first word or part of someone's title, according to Gregg.
What is the difference between anybody and everybody?
Nobody, akin to no and none, means no person at all. Everybody, akin to every and all, means every one of the people referred to. Anybody, akin to any, is in between, and refers to any one or more of the people referred to, but not necessarily all of them.