Learn French: Les paparazzis traquent la star ; ils la traquent tellement qu'elle a peur. - The paparazzi stalk the star; they stalk her so much that she is afraid.

Yes, you could absolutely use tant que here! When modifying a verb to express intensity and a resulting consequence (meaning "so much that"), tellement que and tant que are interchangeable. You could just as easily say ils la traquent tant qu'elle a peur.

Why is la placed before the verb in ils la traquent?

In French, direct object pronouns like la (which replaces la star here) must go immediately before the verb. While in English we say "they stalk her," the French structure is literally "they her stalk" (ils la traquent).

If the celebrity being stalked were a man, would it still be la star and elle a peur?

Yes! The noun star is always feminine in French (la star), regardless of the actual person's gender. Because grammatical gender dictates the pronouns, you must use elle to refer back to it. Even if they were stalking a famous male actor, you would still say elle a peur because elle matches la star.

Why does it say elle a peur instead of using the verb être (to be)?