Of course not. A PS2 is a PS2, not a PSP.
You can download a DLC or add on to a game and use it to play with the UMD game
An average UMD game is about 1GB
Yes it does, it has a UMD drive like the 1000 and 2000.
No you cannot use a umd be to downgrade psp software
If you mean PSP games on UMD, no, the PSP Go does not have a slot for UMD.
The PSN is still down due to a security breach, but when that's back up, you should be able to use that as well as UMD.
Yes you can still use UMD disks in the PSP 3000. However you can not use UMD disks in the PSP Go.
no it doesn't you have to download the game into your psp.
It uses PSP UMD games.
You need the latest version to be able to access the PSN, so just update to the latest, it won't affect your ability to use UMD games.
Yes you can use a PS2 controller into a PC by buying a PS2 to USB connector. This is a connector that tricks the controller into thinking its a PS2.
Shotguns don't use bullets. Do you mean without a case or non lethal projectiles? If so, yes they have caseless ammunition.