how do you say these?

Question

how do you say its too bad you cant come
and i am going to be busy'!
please answer

Answer 1

estaré ocupado'

Answer 2

Es una lástima que no puedes venir.
y
Voy a estar ocupado(a).

Answer 3

estare ocupado and voy a estar ocupado are both correct
but the second one is the exact for i am going to, not i will
and too bad you can't come is ni modo no puedes venir

Answer 4

ES UNA PENA QUE NO PUEDAS VENIR
VOY A ESTAR OCUPADO