They've taken ROMs and sold them to people, it was confirmed some time back. Idk about the emulators, but it would stand to reason that, given they support the ROMs, they've at least looked at other emulators' source code for ideas
No, they hired a guy who had already made an emulator to make theirs. He stuck with the rom file format he already knew. Because the rom files are based on the same source (the released binary on the game cartridge), they are byte-for-byte identical, as you you'd expect.