For #1 you could say "Yo Soy inteligente" wich means i am inteligent or in this case you.
For #2 you could say "Ellos Son intelectuales" wich means they are intelectual.
For #3 you could say "Ellas Son comicas" wich means they are comidians
Yo trabajo en la oficina.
I think u mean learn. so it would be aprender. i hope this helps you.
I beleive you are asking if you should use, " tú " when talking to a child.
True...
In Spanish tú is a unformal way of saying you.
