Would you guys get married the 4th day of your dadz death ?
Depends on the circumstances.
My brother got married 12 days after my grandfather's death. His wedding had been planned in advance, whereas my grandfather's death wasnt. The wedding was tuned down significantly, but went ahead, as life goes on. The girl's side had made plans as well, and its not always possible changing plans on a short notice.
That said, I feel that the reason why people dont get married during Muharram in Pakistan is in order to avoid offending any group of people, not because of religious reasons. And its better to be safe than sorry.