no
Yes they are
The guitar controllers (for PS2) will work, yes. But the drum/mic controllers, no.
You can connect up to 7 controllers. And if people want to use the PlayStation Move while playing, (using 2 controllers) you can have 3 people using it, and have 1 person using the original controller, or 2 people using PlayStation Move and 2 people using original controllers, and etc.
About 8 controllers
YES.
No, you can't use ps2 controllers to play ps3.
2 controllers can fit in the playstation2
No.
The only way that older Playstation 2 dual shock controllers will function with a Playstation 3 unit is through the use of a Usb controller adapter cord which allows the controller to be plugged in through the units Usb port and used.
Yes they do. It works the same with PlayStation games on PlayStation 2 consoles.
No. PlayStation 2 games are not backwards-compatible with the original PlayStation.
No you can not it is not compatible for the playstation 1