Yes, We can marry sheikh's daughters. Thats what the universal brotherhood Islam teaches. There are lot such cases happend. The reason we won't marry is VISA problem, people like you will start again crying like we are not Indians because we are marrying outsiders. Just see even Sonia has to prove her patriotism, so we don't want to put a lady from another country into problems.
Regarding Dawood and Abu Salem, all the allegations are noting but a propaganda by uppercaste to garner votes.
Btw, for us, Both Dawood and MOdi belongs to same category. Irony is that Modi is hero to you.