2. As with everything, it depends how you use them. If you can shelter them from shooting and bring them in on a flank, 4 bases is very neat.
3. The wording is correct. You can have your block 2 wide if you are not worried about the close order bonus.
4. While this is not mentioned in the list, I would have no problem with you fielding the troops in this way.
"No one ever achieved anything without making a few mistakes along the way"