They'll probably just release software emulation for it later down the line... for a price... who knows!
To be honest, I don't really understand why the 40GB version doesn't support PS2 emulation. All the have to do is load up the hard drive with a bit of software, right? Anyway, if you really need to play PS2 games in the PS3, then get the more expensive 20GB or 60GB versions (at least, that's how they're priced here).
The PS2 memory slots have NEVER existed in the PS3. There's an adapter. Anyway, if your son doesn't care about PS2 games or already has a PS2, then the 40GB is good. If he wants PS2 games to work, then again... get the 20GB or 60GB version.
The monitor solution will work, but as FlamySior said, the PS3 has an HDMI connection; not a VGA connection. There ARE cables that can connect a PS3 to a computer screen, you'll just have to shop around. The
Sony message boards might help. After a quick internet search, I found
this and
this.As has also been said, you'll have to hook up the audio cables to something. The obvious thing to do is to hook them up to an amplifier. If you don't want to go so big, I'm guessing that with a mini-Y cable you can plug them into a set up computer speakers.
Hardly! It is a step down, but it's not nearly as stripped down as the 360 core. The 360 core has no hard drive, no wireless controllers, no high-definition output, and no wireless internet support. Even the cheapest PS3 version has all of these things. Not to mention that it can play HD movies.