For question 1 if you select the 'Incorporating a new company' radio button then the form fields will be enabled so that you can fill them out. There is a lot of JavaScript validation used in these form fields so you will need to fill out all of the required form fields in the correct order.
In addition, if you go to Document Properties > Security (Ctrl+D) for this PDF you will see that it has a note: * This PDF form restricts some operations.
Changing the document is not permitted with the exception of filling out the form fields.
This PDF has not been secured in the traditional sense (i.e. with a password) but rather it has been generated in a program such as Adobe LiveCycle with a special digital signature that prevents certain behavior, unlocks hidden functionality in Adobe Reader and prevents this PDF from being opened in non-Adobe applications.
1@pnuts- I need it for change of name. – Arvind – 2013-06-12T11:14:04.783