EDIT 8-11-16 The homes are already built.
33 year old developer Adam Wonus (Facebook) bought up 60 (sixty) 1940s-era homes in the Milk District to demolish and replace with duplexes with average monthly rents of $2,000. Twenty five homes are already gone as of the writing of this post. Wonus is slowly becoming the biggest landlord in the Milk District area according to Orlando Sentinel.
Duplexes are part of whats called the missing middle of urban housing. According to the Missing Middle website, this class of structures "is a range of multi-unit or clustered housing types compatible in scale with single-family homes that help meet the growing demand for walkable urban living. The missing middle are those dwellings that house more than one family but do not disturb the aesthetic personality of a historic neighborhood. These structures include duplex, tri/four-plex, courtyard apartments, bungalow court, townhouse, multiplex and live/work." (source: Missing Middle)
"The current demand for affordable small-footprint or attached housing in the U.S. exceeds supply by up to 35 million units. Most zoning codes limit the types of housing that can be provided. Missing Middle housing types can meet the need for attractive, affordable, well-built housing within the existing framework of many city codes."
What Orlando is seeing is one type of missing middle structure: the duplex. Developers, if they claim to offer lower cost housing, have the option of building tri/four-plex, courtyard apartments, bungalow court, townhouse, multiplex and live/work.
Duplex is not the only style available to developers, but it appears to be the most popular.
The two duplexes on the left were already built before Wonus bought up the 60 lots. The duplexes on the right are his handiwork. Garages facing the street are not typical of historic city-adjacent neighborhoods. These are called snout houses by urban planners. These duplexes are also kept at bay from the sidewalks and streets with imposing driveways, preventing any sort of pedestrian relationship with the neighborhood.
Besides duplexes, there are other ways to introduce affordable housing into a historic urban district. These are called missing middle housing. Cities used to have these interspersed with single family homes. They were design to blend in and mimic single family homes. In the 1950s, many cities banned these structures and only permitted single family homes.