Butternut (Juglans cinerea ) is pretty much the NA equivalent to cedro in terms of it's properties. It's closely related to black walnut (J. negra), and shares the usual walnut stability, but it's lighter and softer. The one workability issue is that it tends to be a bit 'stringy', particularly when scraped. It is sadly available these days; a blight is decimating the trees and a lot of salvage logging is going on. It's too bad: I used to love the nuts.
The best local replacement for mahogany is cherry. It's what the Philadelphia cabinet makers used back in the Colonial era when they were not allowed to import mahogany from the Spanish colonies, and wanted to make their own versions of Hepplewhite and Chippendale furniture. As with all woods it ranges in hardness and density, running roughly from something like a common Honduras mahogany to the harder Caribbean wood. It is close grained, carves and finishes well, and is quite stable.
I've used a lot of persimmon for fingerboards. It's reasonably close in properties to Macassar ebony, but is not normally black, although I've had some that had black streaks. A local tone wood supplier has experimented with a process for dying in black all the way through, with mixed results. There is a process that works well, but it's expensive. A less expensive way to do it tends to not penetrate as well, leaving grey streaks. At the moment he's not selling the wood, which he calls 'Ozark Ebony', since it costs as much to produce as a regular ebony fretboard. I have a few pieces and will use them, in hope that he'll start in again. When I can't get, or don't want to use, the dyed wood, I use a stain made from walnut hulls to color the surface of light woods brown. It doesn't penetrate deeply, but does help to mask dirt and wear marks.
Two other NA woods I've used for fingerboards are American hornbeam (Ostyra virginiana) and soft shell almond (I don't know the botanical on that). Hornbeam is a local native, and is the hardest and densest local wood. It's also called 'lever wood', and 'muscle wood', both of which refer to it's growth habit. These are small understory trees, somewhat resembling beech, but the trunks look corded, as if they were emulating comic book super heros. The wood has strongly interlocked grain, which helps it resist splitting, and that's why it was sought after for use as tool handles and levers. When properly seasoned and well quartered it makes a very nice fingerboard. As it is white to light brown I normally stain it, and the fancy grain makes it interesting. I need to run some tests on the mechanical properties.
Another good NA B&S wood is Black locust ( Robinia pseudoacacia L.). In many respects its an improved Indian rosewood, having similar stiffness, slightly lower density, and damping more like BRW. It bends well and finishes well enough when filled, much like a rosewood.
Many people object to the light color of both Osage orange and black locust. I recently found that both will darken appreciably when fumed with common household ammonia. Locust turns quite dark, while Osage takes on a deep honey color. Both retain their grain pattern and reflectivity.