Is the name "Harun" common in Muslim communities, and if not, is it permissible to name someone "Muhammad Harun"?

It is permissible to be named "Harun" because it is the name of a prophet; in fact, it is recommended, like all other names of prophets and righteous people. It is also permissible to be named "Muhammad Harun," and there is nothing in Islamic law to prevent that, keeping in mind that the names most beloved to Allah are "Abdullah" and "Abdul-Rahman."