Matrix Demos here use the Adafruit::GFX API.
They should work with minimal changes on other backends that support
the GFX API
Aurora is one exception as it does have a few references to direct FastLED style leds addressing using XY() but you should be able to change them to DrawPixel only. It also uses extended DrawPixel which accept both a uint32_t or a FastLED CRBG, but you can fairly easy change those calls to downgrade them back to a native GFX RGB565 if this is all you have support for.
Both FastLED::NeoMatrix and SmartMatrix::GFX provide that GFX+FastLED API as well as an XY mapping function to turn a coordinate into a 1D index for the FastLED backed array (which for SmartMatrix is actually only a framebuffer which is copied back to SmartMatrix's framebuffer later).