I was looking to make an Urban Infiltrator Ranger and was wondering if the two variant classes would not be allowed since Urban Ranger and Infiltrator both affect Favored Terrain.
A character can take more than one archetype and garner additional alternate class features, but none of the alternate class features can replace or alter the same class feature from the core class as another alternate class feature. For example, a paladin could not be both a hospitaler and an undead scourge since they both modify the smite evil class feature and both replace the aura of justice class feature. A paladin could, however, be both an undead scourge and a warrior of the holy light, since none of their new class features replace the same core class feature.
So, no, a Ranger could not have both the Urban Ranger archetype and the Infiltrator archetype since both replace the "Favored Terrain" class feature.
