They are all correct. Other reference manuals, including dictionaries, pick and choose which words to hyphenate when the prefix ends with the same vowel that begins the main word. For example, notice the difference in The Chicago Manual of Style renderings.

Is it reelected or reelected?

to elect someone again reelect somebody (to something) She was reelected to the Senate. reelect somebody (as) something reelect somebody + noun The committee voted to reelect him (as) chairman.

What is the definition of reelected?

transitive verb. : to elect for another term in office.