Question

change these direct questions into indirect questions
what costumes do people wear at the carnival?
do all states in the country celebrate the carnival?
are there any public masquerade balls?
how long does it last?
where is this parade taking pleace?

Answer 1

Si el ejercicio sólo pide  cambiar las frases a preguntas indirectas no hay cambio de tiempo.
Puedes emplear ella/ él  pregunta, quiere saber...ó ellos preguntan. 

She/He asks (wants to know) what costumes people wear at the carnival.
They ask what costumes people wear at the carnival.

She asks if all the states in the country celebrate the carnival.
She asks if there are some public masquerade balls.
She asks how long it lasts. 
She asks where the parade is taking place. 

* No dice nada de reported speech, si fuese así habría que modificar los tiempos.