Cherry Hill ordinances lump "mother-in-law suites" with auto-salvage businesses, junkyards, and heliports as impermissible in residential areas. The township wants to prevent single-family homes from conversion into duplexes or rental apartments, which makes sense. [emphasis added]Um, no, it doesn't make sense. A house with an in-law suite is a duplex/house with apartment. If one family owns a house, adds an in-law suite and then sells that house, the new owners can easily rent out the in-law suite as an apartment. You cannot both want to have in-law suites and not have apartments. The closest you can come is to limit them somehow (no more than 1 suite, and the size of the suite must account for less than 40% of the total square footage of livable space).
Also, what about someone who wants to add an in-law suite for down the road, and is hoping that a few years of renters could help to offset the cost before mom/dad move in?
Particularly in more dense areas (cities and close in suburbs) adding an apartment/flat/in-law suite is an excellent idea, but even if it is only serving as the in-law suite for the original owner, it must be available as an apartment for that value to be realized.