1. Don't believe it, it's hype. Interploated means we can make it seem like more than it is, mostly. 4800 is the real one.
2. Those are how many dots per inch it can do Horizontally & Vertically.
3. Not certain, but likely it's Max resolution.
2400 dots per inch is what it really does, but using motly magical "something for nothing" we can make every dot.pixel be 4 dots/pixels
24 bit output is it's max color scan, which is 8bits each for Red, Blue, & green, though it looks for 16 bits of each to decide how to cut it down.
Always look at the lowest numbers... & make sure it has 10.5.8 drivers.