If LazyTown's children puppets were played by actual children.

Ziggy:

Max Records (season 1-2)

Zach Mooney (season 3-4)

Trixie:

India Eisley (season 1-2)

Nicolette Pierini (season 3-4)

Pixel:

Moises Arias (season 1-2)

Benjamin Flores Jr.  (season 3-4)

Stingy:

Alexander Ludvig (season 1-2)

Jackson Brundage (season 3-4)