1 - Maybe. You could before PSN went down, but we don't know if they'll beef up the protection when it comes back up.

2 - The softmod installer has a test function you can use to see if it'll work or not. If it fails simply reset the PSP's power to fix it.

3 - There's a chance of a brick if you don't read the instructions. If you read and follow the instructions and do the test, there's a very small brick chance.

4 - If it semi-bricks, it's recoverable through 2-3 different methods.

5 - If it full bricks it's dead. The 3000 cannot use a pandora to fix a full brick.

 

If you're scared of full-bricking it, buy a used 2000 that's fully-hackable so you can use a pandora to fix the brick.