Question:
An Allied airborne unit lands in an unoccupied Axis-owned hex that contains an city and becomes disrupted when dropping in the hex. May Axis reinforcements/replacements appear in the city in the Axis initial phase? If so, may they then conduct the same sort of in-hex combat in the combat phase that airborne and amphibious units conduct?

Answer:
Yes.

Source:
Errata published at http://www.hmsgrd.com/Files/Europa/Second Front/Second Front.pdf